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Von den Vorratskammern des Rotfuchses: (Vulpes vulpes L.)1
... Red foxes cache surplus food for future consumption (Macdonald, 1976). When depredating nests, red foxes will often carry eggs away and cache them (Tinbergen, 1965). Red foxes sometimes cache ducks alive (Sargeant and Eberhardt, 1975). ...
... Scent marking commonly involves <20 ml of urine, and is usually of short duration (mean = 2.25 sec, SD = 0.48, n = 40; Henry, 1977). Urine markings apparently serve as dominance displays (Henry, 1977;Macdonald, 1979), social records (Tinbergen, 1965), and as a "no food" signal in the investigation of food remains during scavenging (Henry, 1977). In Poland, frequency of scent marking was 4.41 urine marking and 0.35 scats/km of fox trail (Goszczynski, 1990). ...
... Animal: infantile and adult animals (Lorenz, 1943; reprinted with permission: J. Wiley). Behaviour: the tell-tale corpse-laden trail left by a red fox (Tinbergen, 1965; reprinted with permission: J. Wiley); plants used as crow tools (Holzhaider, Hunt, & Gray, 2010; reprinted with permission: Holzhaider); schematized grasshopper call components (Jacobs, 1950; reprinted with permission: J. Wiley); and a larval caddisfly case (Wallace & Sherberger, 1975; reprinted with permission: Elsevier). Bottom row: experimental design. ...
It is difficult to overstate the value of images in science. Visualization is often the most effective tool to convey scientific concepts, and the opportunities that come with imaging techniques are growing. Nevertheless, we noticed that recent articles in animal behaviour journals include few images of animals or behaviour. To see whether their numbers have declined, we selected five behaviour journals and collected data from 1114 articles published over the journals' histories. We discovered that graphs (x–y plots) have increased over time, charts and tables have not changed, and images (graphical representations, including photographs, of animals, of behaviour, of animals expressing behaviour and of experimental design) have significantly decreased. To test whether supplementary online information has had effects, we compared the use of visual devices in 75 articles with or without supplementary online information. We found that supplementary online information has added means of visually presenting information, but has not compensated for the decline of images.
... Finally, although scatter hoarding does not seem to have a large effect on pilferage risk by wild boar, this effect may be different for other species, depending on the cues provided by the caches and by the hoarder itself, and depending on the search tactics applied by the pilferer. For instance, hedgehogs, Erinaceus europaeus, and red foxes, Vulpes vulpes, which use olfaction to locate buried eggs, have been shown to be able to detect (by smell) eggs buried at 3 cm depth up to a distance of 50 cm and 3 m, respectively (Tinbergen, 1965). After retrieval of a buried egg, hedgehogs only searched in an approximately 1 m 2 area around the cache location, suggesting that scattering individual food items beyond the olfactory detection distance of the pilferer reduces pilferage risk. ...
Food-hoarding patterns range between larder hoarding (a few large caches) and scatter hoarding (many small caches), and are, in essence, the outcome of a hoard size–number trade-off in pilferage risk. Animals that scatter hoard are believed to do so, despite higher costs, to reduce loss of cached food to competitors against which they cannot defend their food reserves (henceforth: superior competitors). We tested the underlying assumption that the cost of having more caches under scatter hoarding, thus increasing the likelihood of cache encounter by superior competitors, is outweighed by the benefit of having small caches that are less likely to be detected upon encounter by superior competitors. We carried out a controlled experiment in which we distributed a fixed number of acorns over a fixed number of patches within a fixed area, varying cache size and cache depth, thus mimicking alternative hoarding patterns. We then recorded cache pilferage by a fixed number of wild boar, a well-known pilferer of acorn caches. The time wild boar needed to pilfer the first cache was shortest for scatter hoarding, but the time needed to pilfer all caches was slightly longer for scatter hoarding than for larder hoarding. Overall, however, the rate of pilferage did not differ between scatter hoarding and larder hoarding, and was not affected by cache depth. We conclude that the effects of alternative hoarding patterns on reducing cache pilferage by wild boar were smaller than expected, and that superior competitors may thus not be important drivers of scatter hoarding. Instead, other factors, such as conspecific pilferage or the risk of cross-contamination of food items in large caches, which can also cause catastrophic loss of food reserves, may be more important drivers of scatter hoarding.
... A seaside colony of black-headed gulls Larus ridibundus was only accessible to the fox if it crossed sand dunes that surrounded the colony. By checking these dunes regularly for tracks, Tinbergen (1965) could monitor the fox' visits to the gull colony over a whole summer. By following the fox' tracks, he could also find buried food such as gull eggs, dead gulls and rabbits. ...
In this review, I will present an overview of the development of the field of scatter hoarding studies. Scatter hoarding is a conspicuous behaviour and it has been observed by humans for a long time. Apart from an exceptional experimental study already published in 1720, it started with observational field studies of scatter hoarding birds in the 1940s. Driven by a general interest in birds, several ornithologists made large-scale studies of hoarding behaviour in species such as nutcrackers and boreal titmice. Scatter hoarding birds seem to remember caching locations accurately, and it was shown in the 1960s that successful retrieval is dependent on a specific part of the brain, the hippocampus. The study of scatter hoarding, spatial memory and the hippocampus has since then developed into a study system for evolutionary studies of spatial memory. In 1978, a game theoretical paper started the era of modern studies by establishing that a recovery advantage is necessary for individual hoarders for the evolution of a hoarding strategy. The same year, a combined theoretical and empirical study on scatter hoarding squirrels investigated how caches should be spaced out in order to minimize cache loss, a phenomenon sometimes called optimal cache density theory. Since then, the scatter hoarding paradigm has branched into a number of different fields: (i) theoretical and empirical studies of the evolution of hoarding, (ii) field studies with modern sampling methods, (iii) studies of the precise nature of the caching memory, (iv) a variety of studies of caching memory and its relationship to the hippocampus. Scatter hoarding has also been the subject of studies of (v) coevolution between scatter hoarding animals and the plants that are dispersed by these.
The brain’s extraordinary abilities are often attributed to its capacity to learn and adapt. But memory has its limitations, especially when faced with tasks such as retrieving thousands of food items—a common behavior in scatter-hoarding animals. Here, we propose a brain mechanism that may facilitate caching and retrieval behaviors, with a focus on hippocampal spatial cells. Rather than memorizing the locations of their caches, as previously hypothesized, we suggest that cache-hoarding animals employ a static mechanism akin to hash functions commonly used in computing. Our mathematical model aligns with the activity of hippocampal spatial cells, which respond to an animal’s positional attention. We know that the region that activates each spatial cell remains consistent across subsequent visits to the same area but not between areas. This remapping, combined with the uniqueness of cognitive maps, produces persistent hash functions that can serve both food caching and retrieval. We present a simple neural network architecture that can generate such a probabilistic hash that is unique to the animal and not sensitive to environmental changes. This mechanism could serve a virtually boundless capacity for the encoding of any structured data.
The present study is the first in a series designed to determine whether or not acute or chronic exposure to ammoniated atmospheres compromises olfactory perception in the pig. Herein, we focused on acute effects of ammonia on food location. As a prerequisite, the relative consumption of a range of 15 odourized visible foods by eight Duroc×Landrace pigs (Sus scrofa) was examined over 15 days in Experiment 1. This enabled us to identify the most and least preferred types for later use in olfactory perception tasks in Experiments 2 and 3. Five of these odourized foods are categorised by humans as sweet (almond oil, peach, raspberry, strawberry and vanilla), six as bitter (anise oil, benzaldehyde, caffeine, cetyl pyridium chloride, eugenol and sucrose octaacetate) and three as sour (acetic acid, butyric acid and propionic acid). A control food treated with de-ionized water was also included. A 250-g sample of each of eight food types was presented in eight food bowls (one sample per food bowl) positioned along the sides of a square pen. Water was available ad libitum. Pigs were tested individually for 30 min. An analysis of variance (ANOVA) showed that the pigs consumed significantly less food when it was treated with eugenol, anise oil or benzaldehyde rather than any of the other odourants (P0.05). Thus acute simultaneous ammonia exposure had no hyposmic or hyperosmic effect on the detection of buried odourized food.
Some red foxes, Vulpes vulpes, urinate very frequently on conspicuous sites. This paper describes such ‘token’ urine marking in detail from observations in the wild (around Oxford, England and Ein Gedi, Israel) and on leash-walking, tame foxes. Field experiments show that token urination occurs at specific sites and in particular areas. A leash-walked vixen reacted differently to her own urine marks than to experimental ones of alien urine, and her reaction was influenced by where she encountered the marks. Token urine marks are most frequently made by socially dominant foxes and are seen in a variety of contexts, including courtship and aggression.
In several field observations, foxes, Spotted hyaenas and other carnivores killed many more prey individuals than they could eat. Functional and causal aspects of this phenomenon are discussed and the conclusion is reached that these surplus kills are the consequence of behavioural compromises in both predator and prey to meet opposing environmental requirements.
(1) Observations are reported in which carnivores killed considerably more prey animals than they could possibly eat, and causal and functional aspects of this behaviour are discussed. The species concerned were especially foxes and Spotted hyaenas, and references are quoted about surplus killing by other Canidae, Felidae and Ursidae.
(2) It is argued that satiation in carnivores does not inhibit further catching and killing, but it probably does inhibit searching and hunting. Thus carnivores are able to procure an “easy prey” but normally satiation limits numbers killed.
(3) Many, if not all, carnivores possess behaviour patterns which allow utilization of a kill at a later time, or allow other members of the same social unit or offspring to use the food.
(4) Several prey species showed a lack of anti-predator reaction under particular climatological circumstances; it is argued that this lack of response usually has survival value. Sometimes anti-predator behaviour is accidentally made ineffective.
(5) Surplus kills are made possible by (2) and (4) above, and only very rare circumstances give a predator access to so many prey that (3) is ineffective. It is suggested that surplus kills are the consequence of behavioural compromises in both predator and prey to meet opposing environmental requirements.
Captive male red foxes were allowed access to urine and anal sac secretions collected from both familiar and unfamiliar foxes of both sexes. Conspecific odors commonly elicited higher visiting and marking frequencies than did their distilled water controls. Unfamiliar odors generally attracted a higher frequency of urinations than familiar odors, and unfamiliar male urine elicited a longer investigation time and was urine-marked more frequently than other stimulus odors.
The first of two experiments with laboratory rats demonstrated that oral estrogen (17 alpha-ethinylestradiol) can remain in the albumen of eggs at room temperature for up to 8 days with undiminished capacity to produce conditioned taste aversion. The second experiment showed that estrogen remains potent in the yolk of eggs for at least 4 days. There is now greater assurance that egg prey placed into the field will induce reliable CTA among mammalian predators. Community ecologists interested in such processes as competitive release and the responses of prey populations to reduced predation upon their eggs can selectively factor predation out of field experiments without the need for physically excluding predators. Wildlife biologists interested in reducing predation upon the eggs of endangered species now have greater assurance that estrogen-treated egg baits will suppress predation in a more cost-effective manner and with less likelihood of discrimination between treated eggs and those of endangered species.
