Animal Communications - Science topic

Joanne P Ballard

You wrote: "could paleoindians or other Pleistocene peoples have gained the confidence of woolly mammoths or mastodons to use them as transportation and other tasks, the way that Asian elephants are used today?"

They could have, on a very limited basis, in some unusual circumstances, but they didn't. For the uses you suggest to be put into practice and become relatively prevalent, a somewhat more advanced civilization or level of development is required and that came later. Still, it's an intriguing thought. What might paleopeople have accomplished with mammoths or mastodons in building pyramids or henges.

Intelligent Reflecting Surface IRS be designed for 1 to 6 GHz bands:

1- Cascaded Channel Estimation for Intelligent Reflecting Surface Assisted Multiuser MISO Systems

2- Terahertz Multi-User Massive MIMO With Intelligent Reflecting Surface: Beam Training and Hybrid Beamforming

3- Wireless Environment as a Service Enabled by Reconfigurable Intelligent Surfaces: The RISE-6G Perspective

4- Joint Beam Training and Positioning for Intelligent Reflecting Surfaces Assisted Millimeter Wave Communications

5- Intelligent Reflecting Surface (IRS) Allocation Scheduling Method Using Combinatorial Optimization by Quantum Computing

5- A Path to Smart Radio Environments: An Industrial Viewpoint on Reconfigurable Intelligent Surfaces

6- System Performance Insights into Design of RIS-assisted Smart Radio Environments for 6G

7- Slotted Wideband Frequency Selective Reflectors for Sub-6 GHz 5G Devices

Yes, IRS can be deployed to enhance security in communication networks to either replace legacy security solutions or supplement them.

IRS or no IRS, isn't this a standard problem of propagation loss? You have to know the sensitivity of the receiver, the noise power at the receiver, the gain of the receive antenna, the range to the transmitter, the terrain characteristics, and consequent signal loss along the path, and the transmit power and transmit antenna gain.

Now, without IRS involved, you can compute the signal to noise ratio at the receiver, and determine if communications are possible, using a given type of modulation. There will be different marginal SNR requirements, depending on type of modulation you want to use. Shannon's equation can be used, to predict the maximum possible channel capacity, along a single propagation path, with a given channel bandwidth and SNR.

I'd say that using IRS, at either or both ends, is much the same as changing transmit and/or receive antenna gain.

Dear Abbas Thajeel Alsahlanee ,

Welcome!

As far as I understand the IRS is one hop network component. If the path from the source to destination has low transmission coefficient such as deep fading of massive blocking then one can use one ore two IRSs to convey the signal to the intended receiver or destinations.

Incase of more that one IRS all of them receive their incident waves from the intial source such as the base station. I think multi hops may cause excessive delay.

Best wishes.

An IRS is a new type of relay, with specific characteristics, benefits, and drawbacks. This is discussed in our recent magazine article: https://arxiv.org/pdf/2006.03377.pdf

The increase in a delay spread caused by an IRS is rather small, so ISI isn't really the problem. However, when an IRS is tuning the propagation environment for one communication link, it can accidentally cause interference to other communication links (in the same or different bands).

Dear Abbas Thajeel Alsahlanee ,

welcome!

I think the IRS technology for controlling the the wireless transmission parameters will undergo tremendous research to apply them in the the 6G mobile communication networks.

I think I wrote about this before for answering one your questions on this topic.

To be aware of the challenges and difficulties with the introduction of such devices please follow the paper in the link: https://hal.archives-ouvertes.fr/hal-03020450/document

Best wishes

Dear Abbas,

I will recommend the article https://arxiv.org/pdf/2104.01421.pdf

I hope it will be worth reading about your problem.

Yes, you can use the technology at any frequency band and for many different use cases. The main question is what kind of problem the addition of an IRS will solve. One possibility is to deal with Doppler effects: https://arxiv.org/pdf/2006.06991.pdf

Dear Abbas,

I suggest you to see links and attached files on topic.

Best regards

Dear Abbas Thajeel Alsahlanee ,

welcome!

It is so that the the signal path from the base station shows multipath effects such as fading to the user site.

The addition of the IRS will introduce an alternative path where the signal will be recieved by the IRS phase shifted and amplitude changed and directed to the the site of the user equipment. So the signal path through the IRS must has better transmission properties which means higher signal to noise plus interference at the user site.

So, Accordingly one has to maximize the signal to noise plus interference ratio.

Best wishes

yes! DM

Hi Joni,

I have always referred students who ask about basic acoustic processing in sharks, skates and rays to this now classic paper by Jeff Corwin:

Corwin J.T. (1981) Audition in Elasmobranchs. In: Tavolga W.N., Popper A.N., Fay R.R. (eds) Hearing and Sound Communication in Fishes. Proceedings in Life Sciences. Springer, New York, NY. https://doi.org/10.1007/978-1-4615-7186-5_5

Of course if you are specifically interested in the acoustic "signals" produced by these animals rather than the detection of such signals, then I will keep looking.

Hope this helps.

Peter

Dear Andrè,

You should take a look at Fonoteca Zoológica of the National Museum of Natural Sciences, Madrid, ─ http://www.fonozoo.com/; Maculay Library of the Cornell Lab of Ornithology, New York ─ https://www.macaulaylibrary.org; and the Fonoteca Neotropical Jacques Vielliard of the Campinas State University, São Paulo ─ www.2.ib.unicamp.br/fnjv/).

The are the three references for anuran calls.

Good luck,

Cristian.

Solomon coder (https://solomoncoder.com) is a really handy and flexible program for video coding with extended features for exporting data and even some preliminary analyses.

Hi Adwait!

Have you checked warbleR ? This is a free R code developed by Marcelo Araya-Salas to streamline analysis of animal acoustic signals. 

Probably this is what you are looking for, although you must have some knowledge of R to use.

All the best!

Thank you~

Sorry, this first file didn't upload properly. Here it is.

Hi Laura,

I agree with Pavel regarding the channels and amplitude. I also don't use SoundRuler (sorry!) but I thought it might be useful to add that you need to be sure there is no background noise overlapping your calls of interest. If for example these recordings were made at a zoo, there may be visitors chatting, or in the field there could be other animals calling etc. on your recordings. If there is, then you can either need to filter it (if it does not overlap in frequency with the monkey calls), or if that's not possible, you could manually extract the frequency measures, or simply eliminate those calls from your analyses. It might be that you can use the read-out on all your "clean" calls (i.e. no background noise, one individual calling at a time) and in that case it could be just as simple as you say!

Good luck with your interesting project!

All the best,

Esther

When I was working on turtle vocalization ion the '80s, I put the animals from my lab in a small pen and sat outside it to record their vocalizations and simultaneous behaviors. These female and male chelonians, first- and second-generation pancake tortoises and N.A. box turtles deliberately bonded with humans, had learned to mimic certain of our unvoiced phonemes, mainly /p/, /t/, /s/ /k/. What was surprising was that all of the vocalizations were directed to me--none to each other. I suspect the attention to the human was related not only to the bonding but also to the gestures the animals had "invented," if you will, for eating, drinking, and to be picked up, in this case, the latter. They were unaccustomed to being penned. As far as we know, wild terrestrial turtles do not ordinarily vocalize to each other, with the exceptions of the South American river turtles vocalizing to their young and in open-mouth agonistic encounters. Males only (50-some tortoise spp. identified) vocalize during mating and the latter stages of courtship. The chelonians in my lab, including two parents dating from the '70s, also learned to understand the referents of some human words, which ability they could demonstrate. Whether there is a particular locus in the turtle brain that enables that understanding or whether a more generalized cognitive ability is used is only speculation.

Johnathan maintains an active listserv for his DMDX program: http://www.u.arizona.edu/~kforster/dmdx/list_serv.htm

Tell him I recommended you to join = )

Articles on ear evolution:

Regards,

Joachim

HI, you might want to check with Phil Lobel and David Mann, they would be the most likely to have recorded the species.

Please check the following links.

You're most welcome. Clearly, Arendt, Hofstadter, and the gang would never pass academic muster these days. SIGH! Of course, I think the methodological games, to some extent, serve as a way to suppress critical thinking about larger issues. Hmmmm.

Anyway, I hope life is treating you with gentleness.

Best,

Cath

Hello Alice, I saw "fruit bat curry" on the menu of a restaurant on Praslin/Seychelles in 2009. So the observation of Hans Hollander in 1991 can be confirmed in this day and age. 

Please have a look at these links.

Dear fellows,

I've been watching your discussion related to "Do fish measure reactive intensity?" and found it interesting when talking about "total sound intensity from a pure acoustic point of view". When it comes to sound reception/sensing in fish you've forgot the "most" important sensor beside the swim bladder and the lateral line, i.e. the otoliths, which act like an accelerometer. There is some literature related to this which may clarify/elucidate sound reception in fish in relation to total sound intensity. I'll like to see you++ continue with this discussion.

sure, if you send me a template file I will take a crack at it and send you a set of m-files. I would consider it a fair trade, I haven't had a chance to work with whale song much lately.

According to Jud & Layman 2012 lionfish are capable of making an audible noise when disturbed.

Hey John - interesting question(s).  I will take this in 2 parts.  First, if O2 can limit or influence drivers of melanin-based signals.  I have little idea if or how there could be a direct relationship, but I very much doubt it.  There are just too many other things going on.  Second, on the relationship of elevation and phenotype: yes, very clearly there are connections between physiology and phenotype and elevation - most notable are the adaptations and phenotypic plasticity observed at high elevations.  I think fence lizards (Sceloporus) show some pretty amazing differences (See Leache et al, Biological Journal of the Linnean Society, 2010, 100, 630–641).  There is also going to be tremendous correlation with anything that can vary phenotypically that is related to overall metabolism and response to the difference in temperature (as you mention).  But the big answer here is: its too complicated to generalize.  The small answer depends on your system, the organism(s), and the elevational gradient.  Clearly there are many other things can can co-vary with elevation, but there are also artifacts (soil differences, humidity regimes) that might not have anything to do with elevation per se - and could skew your analysis.  If your system is birds - and they can fly, I would be very careful in how you attribute difference in elevation to any phenotypic differences, since the birds might be able to be in habitats every day that differ in elevation by >1000m.  So unless you have extremely low-motility philopatric animals, where you actually see or catch the birds might not be a good indication of the preferred habitat of the individual.  If you can make some fairly clean relationships between O2 and elevation and coloration, great.  But I reckon it is much more complicated than that and you can find much clearer relationships between say temperature and coloration.  Good luck with your research!

thanks professor!

as mentioned before there are two problems, storage and batteries. Among small digital recorders the best one is the SONY PCM-M10, unfortunately now discontinued but still available in US. Its power consumption is among the lowest: 60-70mAh, that means >30 days continuous recording with 6 or 8 D size batteries (max 18Ah at 1.5V), that brings weight and size high. As an option you could use Lithium D size batteries, expensive but with double power than alkaline (up to 19Ah at 3.6V).

As for the storage the M10 is one of the very few that is declared max 32GB but can record on a Sandisk Ultra 128GB microSDXC formatted by a PC in FAT32 mode. The max microSD size now available is 200GB but I never tested it in the SONY. Huge size available; however, to record 30 days you necessarily need to switch to MP3-320K with a bandwidth of 15 kHz, that is more than with 22k PCM sampling.

In 22kHz PCM stereo (few recorders can record in mono !) you need 228GB/month that would be possible with a standard 256GB SDXC card (these are also available up to 512GB now). But recorders are larger and more power hungry.

Solutions based on microcomputers need too much power. In any case the first feature you must check is power consumption. A recorder that would partially fit your needs is the Tascam DR22WL, it records in mono and thus 1 month could fit in a 128GB microSDXC card. Unfortunately it requires near to two times the power required by the SONY M10. If you solve the battery problem the WL 22 is the good solution.

Another option to be deeply tested before going on is to use the ZOOM H1. Smaller and lighter than the SONY, It is declared to max 32GB microSD however it can record on larger memories as the SONY (to be tested on specific memory brands and to be tested for power requirements).

Eventually write me privately for alternative options.

Gianni

Dear Karyn,

Our foundation has been funding for several years a project which has developed an automatic detection system. This has been designed to detect, extract and store in a database killer whale vocalizations but theoretically it should work with any sound event. It would be great to have one of your recordings to make a test and, if if works, we can find the way to process your  recordings, as the system stills under development and there is no a version for distribution yet.

J

Thank you, I suspected that there aren't longitudial studies on this species..

I am not related to the subject. Still I am trying to answer by using the Paper attached at link.

Human language can express limitless meanings from a finite set of words based on combinatorial rules (i.e., compositional syntax). Although animal vocalizations may be comprised of different basic elements (notes), it remains unknown whether compositional syntax has also evolved in animals. Here we report the first experimental evidence for compositional syntax in a wild animal species, the Japanese great tit (Parus minor). Tits have over ten different notes in their vocal repertoire and use them either solely or in combination with other notes. Experiments reveal that receivers extract different meanings from ‘ABC’ (scan for danger) and ‘D’ notes (approach the caller), and a compound meaning from ‘ABC–D’ combinations. However, receivers rarely scan and approach when note ordering is artificially reversed (‘D–ABC’). Thus, compositional syntax is not unique to human language but may have evolved independently in animals as one of the basic mechanisms of information transmission.

The most important thing to understand about Raven's band-limited energy detector (BLED) is that it is an extremely non-specific event detector. It simply finds events where the energy in a rectangular time-frequency box exceeds an estimate of the background by a specified threshold. In configuring the detector you define the lower and upper frequency bounds, and minimum and maximum duration. (This is a somewhat simplified explanation; there are a few other parameters you need to specify as well.) It is not able to discriminate among sounds with different shapes or features in a spectrogram if they are of similar duration in the target frequency band. It can work well at finding your targets if l if (a) your target signals are consistently in a given not-too-wide frequency band, (b) have high signal-to-noise ratio, (c) are not often overlapped by non-targets. If there are a lot of non-targets that occur in the same band and have similar durations to your targets, you will get a lot of false detections. Depending on the characteristics of the targets and the clutter, it may or may not be easy to separate them later based on measurements. The more your targets vary in structure, the harder it will be to achieve good detection without lots of false detections (this is generally true of any autoimatied detection algorithm). Whether it works well or not in a given situation is simply a matter of the characteristics of the targets, the clutter (non-targets), and the noise environment. In real-world noisy recordings the results are often disappointing. 

In addition to the other answers, I'd suggest to explore the use of cepstrum analysis to reveal the pulse rate and pulse rate modulations within the bursts. 

Gianni Pavan

I know a Biologist who is expert in vocal communication of New World primates.  His name is Enrique Zerda.  Please let me know if you think his contact could be useful for you, 

Thanks Sreejith. I could link to the sites of CTFS and RAINFOR, but not GEM (What is its URL?). Please specify some publications in which I can get what I am looking for. Regards.

This is a really interesting question. IF chest beating is an honest signal of male strength - which probably most people think it is - then you would EXPECT that the signal should decline with increasing age, because honest signals are costly to develop and maintain and as individuals age it should become harder to maintain the same signal strength. However, I am not aware of an empirical study that has looked into this question. You will need to make recordings of chest beating in different aged individuals and if possible also recordings of the same individuals over time (may take a couple of years to collect such data). Then you will need to analyze the sound files and test if there are statistical differences that can be explained by age.

If there is only one animal calling there, it is possible that you have a kind of nonlinear phenomena common in mammalian vocalizations (biphonation). So, you probably have two independent fundamental frequencies (as you can see in the vocal units from the middle of the call on). It seems that at the begining of the sequence the animal is producing tonal calls that the fundamental is the F0. Then you have the biphonation happening.

Please, find more about biphonation in these papers:

Riede, T., Herzel, H., Mehwald, D., Seidner, W., Trumler, E., Tembrock, G. & Bo¨hme, G. 2000: Nonlinear phenomena and their anatomical basis in the natural howling of a female dog-wolf breed. J. Acoust. Soc. Am. 108, 1435—1442

Fitch, W. T., Neubauer, J. & Herzel, H. 2002: Calls out of chaos: the adaptive significance of nonlinear phenomena in mammalian vocal production. Anim. Behav. 63, 407—418.

It sounds like an interesting project, however it will be much easier for people to help if you tell us: what frequency and duration of sampling will you need, in order to address your research questions?

In favourable conditions you can get good video and sound recording with almost any compact digital camera, even with older models as Tessa mentioned. And you can easily mount a compact camera on a low tripod or other stand and add a rain-proof cover (or choose a waterproof model), place it near your study animals, turn on video mode, walk away and leave the camera to run continuously...

...until the battery runs down or memory card fills up... maybe half an hour, maybe an hour or two, depending on camera, memory and video settings.

Much more challenging if you want to record continuously all day, day after day. You will need external power and high capacity data storage... and afterwards you will need to spend many days watching/listening in order to extract the data of interest.

Some other considerations: can you work near these animals (set up equipment, change batteries, etc) without disturbing the behaviour you are studying? Can you predict fairly accurately when and where the behaviour of interest will occur?  How near and how far from the recording equipment do you expect the animals be heard/seen? Do you want the vision to be clear and close enough to identify age/sex/other characteristics? How much ambient noise from wind or road traffic or other sources? How many animals do you want to record concurrently?

I would suggest to consult the following monograph, which includes generalised distribution maps of stichodactylid anemones:

Fautin, D. G. & Allen, G. R. 1992. Field guide to anemonefishes and their host sea anemones. Perth (Western Australian Museum), 160 pp.

Dear Ricardo

this paper full of some point. maybe, help you.

Hannah:  Good Morning.  I have attached some papers that may give you some direct leads as to specific people to talk to directly.  One person that I would recommend is Dr. Gisela Kaplan who I am most familiar with as to her work on Australian Magpies, a species that we exhibit at my zoo.  She has done some comparative work of Magpies to other species such as Lyrebirds when it comes to vocalizations.  Hope this will move you along in your work.  Best wishes.  Thane G. Johnson, Oklahoma City Zoo

Yes I found the horse grimace scale on PlosOne (Dalla Costa et al). I am now looking for something that distinguishes the signs from anxiety (which may not be possible due to the shared pathways). Looking for research articles themselves rather than websites, as need the actual research data. However, many thanks for following up on these.  I was originally from NZ and do like your website. Wendy www.equinefreelance.com

Rafael,

I revisited all the posts.  On page 1, the conversation focused on what could be an appropriate animal culture concept then on page 2 you moved the discussion on the topic of consciousness and from there the discussion diverged from the topic of the thread.   I personally believe that the study of animal cultures , an animal anthropology is potentially conducive to a lot of insights about what it is it to be humans.  Like all anthropological study, it has to involve a degree of participation into the culture.  One area where this is possible for humans to participate into an animal culture is music.  A few researcher musicians have began to engage into animal music.  Music is a very important form of culture given that it is probably at the root of the primate human cultural transition.  Humans are probably the results of a long cultural journey that began with the leadership of a musical Eve.  A new form of dancing singing for emotional tribe control was probably the first form of religion , the first language and the road that has allowed the control conscious access to the mammalian self-enactment narrative capacities.  All mammals have these self-enactment capacities but they are used for sensory-motor learning and integration without any direct access to it.  The dancing singing social leadership hypothesis could be investigated through trying to engage bonobos through some forms of dancing singing practices.

 In Descent of Man Charles Darwin  wrote:

"When we treat of sexual selection we shall see that primeval man, or rather some early progenitor of man, probably first used his voice in producing true musical cadences, that is in singing, as do some of the gibbon-apes at the present day; and we may conclude from a widely-spread analogy, that this power would have been especially exerted during the courtship of the sexes,--would have expressed various emotions, such as love, jealousy, triumph,--and would have served as a challenge to rivals. It is, therefore, probable that the imitation of musical cries by articulate sounds may have given rise to words expressive of various complex emotions."

Also in Descent of Man, Darwin  suggested that modern music is a “fossil”

of a former adaptation: an earlier hominid communication

system or “musical protolanguage.” This is an

idea of considerable merit that has been rediscovered by

many subsequent authors (e.g., Brown, 2000; Jespersen,

1922; Livingstone, 1973; Mithen, 2005; Richman, 1993)

A review of The Singing Neanderthals: The Origins of Music, Language, Mind and Body by Steven Mithen.

This sounds like a long-range communication call. These are often used while moving fast in the  dense canopy, and when pair or flock members are separated by the distance of 10-15 m at least. 

I don't think you can do it, unless you know what is the proportion of animals you have telemetry data on. Otherwise, there is no information on resights of a sample of tagged animals on the proportion of untagged animals, and hence you can't get density/abundance. At best, if you have a large and representative sample of animals for which you have telemetry, you can construct a RELATIVE density surface, which essentially would represent habitat use (assuming you get locations  independently of habitat, which might or not be true!). But you have no information on the telemetry data alone to inform about the height of said function. I believe the references provided by @Rishi Kumar Sharma are only useful if you have BOTH telemetry data and additional information (e.g. captures and recaptures of both telemetry and non telemetry animals), which is clear form the wording in the title ("....radiotelemetry and replicated mark-resight techniques..." and "....radiotelemetry and replicated mark-resight techniques...") 

There's a recent paper on spatial referential gesturing in bonobos: http://www.cell.com/current-biology/abstract/S0960-9822(14)00666-6

In terms of actual chemical characterization, none have been described (to my knowledge). However, Fraker et al 2009 (Horm Behav) showed a nice neuroendocrine response from a skin-released compound in larval amphibians. Fish have been well described (e.g., ostariophysan alarm pheromone). The Fraker paper has a nice summary of what is known as well. I doubt my answer helps, but I would also love to know if you have any updates on this question.

This is a interesting article titled "SELECTED VOCALIZATIONS OF THE COMMON CROW"

Herman, L.M., R.K. Uyeyama (1999). The dolphin's grammatical competency: Comments on Kako. Animal Learning & Behavior. Vol. 27:1, p. 18-23

ABSTRACT

Kako (1999) reviews the evidence for syntactic competencies in several animal species exposed to artificial language systems, emphasizing the importance of core syntactic properties such as argument structure and closed-class items. We present evidence from our dolphin studies for the acquisition of the closed-class functionality of demonstratives, prepositions, conjunctions, and locatives. Sensitivity to argument structure is also evidenced by wholly untrained and consistent interpretations of the dolphin to probes of anomalous syntactic structures. These results are generated within our comprehension-based paradigm, which enables us to provide convincing objective evidence for the development and generalization of concepts by the dolphin subject. Demonstrations of animal language competencies may illuminate certain aspects of human linguistic competence by suggesting that the particular modeled subsets can derive from general cognitive mechanisms, rather than language-specific ones.

I imagine that you're finding that much of the literature will comprise of studies that must be interpreted to fit the definition of humor (rather than simply calling it "humor"). In my opinion--and I think the opinion of my undergraduate mentor, Don Griffin--is that a given human phenomenon must been defined in a currency that is measurable in animal. In this case, I would be interested in your working definition of humor...

If humor can be defined (as Wikipedia states) as the "tendency of particular cognitive experiences to provoke laughter and provide amusement," then researchers of humor in non-humans must be able to assess/quantify what constitutes a cognitive experience and also find behavioral responses that are akin to laughter and amusement. I imagine that we could define laughter than defining certain frequency characteristics of vocalizations (as well as their temporal features), as the paper posted by Ali does. I do think this paper does something interesting. It describes mechanisms of what could be called "laughter." So, at least for apes, researchers could then look for instance of laughter in other contexts (such as when another ape falls off a branch). This could indicate the presence of a cognitive experience. But, then again, this is based on the assumption that the "laughter" of apes operates across contexts, as in humans. What if the manifestation of humorous experiences in apes is a simple nod of the head? How, then, can we compare the function of humor of humans and other animals? It's a difficult question.

Don Griffin stressed to me that the key to understanding how to study the animal mind is through the study of communication. That's a difficult job, of course, simply because we are then tasked we deciphering complex communicative behaviors of individuals across contexts...

This was my very long way of asking what the working definition of "humor" is, and how is it measurable among species? I think such comparative cognition studies should move towards explicit quantification.

I assume you are talking about researchers using/studying animals. Although it's a bit old now, you should look for "The Inevitable Bond: Examining Scientist-Animal Interactions", pub 1992 by Cambridge and edited by Davis and Balfour. But there is now a large literature on human-animal studies, with specialist journals, which you should seek out.

Dear Leyla,

I am not sure if you find this relevant but schooling fish tend to avoid conspecific individuals that show different/aberrant behaviour. For example some parasites induce behavioural changes in fish which cause avoidance by conspecifics (eg. Barber et al. 2000 Rev Fish Biol Fisheries 10: 131-165; Krause & Ruxton 2002. Living in groups. Oxford). A general explanation for group avoidance and/or aggression towards aberrant individuals is that they can potentially disrupt the anti-predator benefits of the group, for example by reducing the vigilance of the group and/or making it more conspicuous to predators. Thus avoidance and/or group aggression against "outlaws" and other abberrant individuals may in some cases have evolved as a response to predation pressure, although this is probably less likely in top-predators like wolves which was one of your examples. To what extent this explanation is relevant for humans I do not know, this may be a bit speculative. However, predation pressure from large predators was likely one of the main reasons (the other was cooperative hunting) that our ancestors formed increasingly larger groups when adapting to the open savannah so...

Best wishes

Jörgen

In addition to Sean's story: I've made friends with some

crows. One of them, the bravest one, I named Friedrich,

in honour of Frederick II who wrote a book on ornithology.

Friedrich got the most walnuts since he dared to

approach me closest. Unfortunately he was constantly

being attacked as soon he was in the air with the

nut, before he was able to find a hiding-place.

On one day Friedrich obtained a walnut and was soon

building a concealment for it near me, in the presence

of a greedy fellow crow. I was wondering because hiding

made no sense here.

Friedrich covered the nut with moss while being watched.

Then he presented his back to the other crow, thereby

covertly snatching the nut with his beak. He flew away.

The other crow approached the supposed tibit and

got aware that it was being fooled, but it was

too late. Friedrich and the walnut were in safety.

Regards,

Joachim

Jessica: I checked with my staff and they tell me that they see the head quivering fairly frequently with both parma wallabies and red kangaroos. They seem to do it for no particular reason- it doesn't seem to be a stress response or a breeding behavior. We've never seen any of the macropods spray urine at each other. Keep in mind, however, that our parma wallabies (although recently descended with wild caught imports) have never been housed with more than one mature male in the mob. Our red kangaroos, on the other hand, are descendants of many generations of captive breeding. We've had more than one adult male in that mob, but old was older and probably did not pose much of a social threat to the breeding male.

A colleague of mine: Robert Cook has an excellent online book that covers avian visual abilities:

Including equivalence class formation stuff which you might be interested in.

Also I have a paper comparing 4 species and their ability to form and use rules in category formation:

Smith, J., Berg, M. E., Cook, R. G., Murphy, M. S., Crossley, M. J., Boomer, J., & ... Grace, R. C. (2012). Implicit and explicit categorization: A tale of four species. Neuroscience And Biobehavioral Reviews, 36(10), 2355-2369. doi:10.1016/j.neubiorev.2012.09.003

Joshua Akey et al published a paper in PNAS a few years ago on

identifying regions of the canine genome that have been substrates of

artificial selection (http://www.pnas.org/content/107/3/1160.full). CTNND2 was one of the genes (or more accurately, a gene in a broader genomic region) that showed up as having unusually high levels of genetic differentiation between Collies and other breeds.

I would suggest consulting the review article by Murphy et al. (2009), "What Horses and Humans See: A Comparative Review", published in the open-access International Journal of Zoology ( http://www.hindawi.com/journals/ijz/2009/721798/ ) -- a pdf of the paper is attached. In their review of the literature, the authors indicate that the available data suggest that horses have relatively poor visual acuity relative to humans. They also note that motion detection, especially for predator avoidance, would be a key visual adaptation in horse behavioural ecology. They go on to state that a full and complete understanding of what horses experience visually is still some way off. Both my daughters are riders and own a horse between them; from watching their equestrian competitions, I would say if you want to know what a horse is looking at, pay attention to where their ears are pointed.