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Introduction
Skills and Expertise
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August 2010 - May 2016
Publications
Publications (54)
Several legal acts mandate that management agencies regularly assess biological populations. For species with distinct markings, these assessments can be conducted noninvasively via capture‐recapture and photographic identification (photo‐ID), which involves processing considerable quantities of photographic data. To ease this burden, agencies incr...
Bow-riding occurs when dolphins swim in the pressure waves at the front of a vessel. Bow-riding is hypothesized to be “fun” for dolphins or to save them energy although the energetics have not been explored. An UAS (Unoccupied Aerial System) was used to follow and video-record adult dusky dolphins (Lagenorhynchus obscurus) bow-riding in front of a...
Pharmaceuticals prevent and treat diseases, yet inappropriate intake can result in harmful effects including mortality. Contaminants have become recurrent public and wildlife health concerns. Bioaccumulation of contaminants can occur throughout trophic levels of the food web. Dolphins are apex predators often used as sentinel species to assess the...
Bottlenose dolphins (Tursiops truncatus) inhabit environments with variable natural salinities and experience physiological imbalances from extreme salinity fluctuations. Low salinity exposure (≤10) disrupts osmoregulation and increases the production of steroid hormones aldosterone (electrolyte balance) and cortisol (stress response). The effect(s...
For 88 years, biologists and engineers have sought to understand the hydrodynamics enabling dolphins to swim at speeds seemingly beyond their energetic capabilities, a phenomenon known as Gray’s paradox. Hydromechanical models calculating the drag of swimming dolphins estimated power requirements for sustained high-speed swimming, which were physio...
Anthropogenic activity in coastal areas can damage marine habitats and alter marine mammal behavior and habitat use. Understanding behavioral associations with diverse habitat features in industrialized coastal areas is crucial for marine mammal conservation management. A shore-based digital theodolite was used to assess the behavioral states and h...
Bottlenose dolphins (Tursiops truncatus) inhabit waters across a broad natural salinity gradient and exhibit changes in skin condition based on the quality of their environment. Prolonged exposure to low salinities (≤10–20 ppt) degenerates the epidermal barrier and causes cutaneous lesions in dolphins, while the role of high salinity exposure (>35...
Short-term behavioural responses have been documented in cetaceans exposed to anthropic activities. Increase of swim speed have highlighted how cetaceans can exhibit a flight response when disturbed. While it is possible to quantify variations in swim speed, it is challenging to predict the physiological consequences of such behavioural changes. Th...
Pinnipeds (seals, sea lions, fur seals, and walruses), cetaceans (whales, dolphins, and porpoises), and sirenians (manatees and dugongs) spend most of their lives beneath the surface of the water. Each clade has distinctive reproductive cycles that more closely resemble their terrestrial relatives than other marine mammal groups, although patterns...
Although the Port of Corpus Christi, Texas, has become a top oil exporter, it is unknown if local dolphins are disturbed by high year-round vessel traffic. A shore-based digital theodolite and automatic identification system receiver were used to record data to assess common bottlenose dolphin (Tursiops truncatus) behavioral states and movement pat...
Mating and sociosexual behaviors of cetaceans are challenging to study in nature because most species spend only brief periods of time at the surface and most copulation and courtship occurs underwater. Recent advancements in technology have enabled a new perspective on these behaviors. Drones, or unoccupied aerial systems, have revolutionized stud...
Dusky and spinner dolphins are small-bodied odontocetes that show variation in socioecology across their range. New Zealand dusky dolphins and Hawaiian spinner dolphins of deep nearshore waters feed nocturnally upon prey species associated with the deep scattering layer, leaving the daytime free for rest and social interaction, often close to shore...
Among the taxonomic family of porpoises (Phocoenidae), mating behavior in nature has been described in detail only for the harbor porpoise ( Phocoena phocoena ). We review this species’ unusual mating habits based on a study in San Francisco Bay, California, USA, and present new data from across its range in the North Pacific, North Atlantic, Black...
The relationship between sexual selection and the diversity and rapid evolution of male genitalia has been well-documented across many animal taxa, while the morphological variability of female genitalia has received comparatively little attention. Female whales, dolphins, and porpoises possess unusual flaps, folds, and blind sacs in their vaginas,...
We provide a conceptual primer for sexual selection and conflict, mating systems, and socio-sexual behaviors and patterns among animals, largely with mammalian and cetacean examples. The important roles of mate choice are discussed (including female choice) and the occasional fluidity of sexual roles. An overview of topics pertinent to sex and beha...
Researchers can investigate many aspects of animal ecology through noninvasive photo–identification. Photo–identification is becoming more efficient as matching individuals between photos is increasingly automated. However, the convolutional neural network models that have facilitated this change need many training images to generalize well. As a r...
This paper describes the first documented obseravation of placental expulsion by a long-finned pilot whale (Globicephala melas), which was captured on video by an unmanned aerial system (UAS) in coastal waters of the Shetland Isles, Scotland, United Kingdom. The advent and development of UAS technology provides novel opportunities to observe and do...
Dolphins are often individually identified by unique naturally-acquired markings. Identification becomes difficult when markings heal, or new scars appear. As salt accelerates wound healing in many organisms, the diminishment of scars on common bottlenose dolphins (Tursiops truncatus) residing in varying natural salinities was determined. South Tex...
The evolution of female genitalia has historically received less attention than male reproductive organs. Several papers have underscored the disparities in research efforts, but have calls for change resonated with the scientific community and rectified the skew? A literature review was conducted of journal articles published between 2013 through...
In species that copulate during non-conceptive periods, such as humans and bonobos, sexual intercourse is known to be pleasurable for females. Dolphins also copulate throughout the year, largely to establish and maintain social bonds¹
• Mann J.
Establishing trust: Socio-sexual behaviour and the development of male–male bonds among Indian Ocean bot...
The field of post-copulatory sexual selection investigates how female and male adaptations have evolved to influence the fertilization of eggs while optimizing fitness during and after copulation, when females mate with multiple males. When females are polyandrous (one female mates with multiple males), they may optimize their mating rate and contr...
Comparisons of 3D shapes have recently been applied to diverse anatomical structures using landmarking techniques. However, discerning evolutionary patterns can be challenging for structures lacking homologous landmarks. We used alpha shape analyses to quantify vaginal shape complexity in 40 marine mammal specimens including cetaceans, pinnipeds, a...
Few studies have explored the mating patterns of free‐ranging cetaceans, largely because of logistical challenges. We used an unmanned aerial vehicle (UAV) to follow and video‐record 25 groups of mating dusky dolphins (Lagenorhynchus obscurus) near the surface of the water and examine how behavior patterns varied with mating group type. We collecte...
In internal fertilizers, copulatory behavior and genital morphology are intricately connected because there are many functional and morphological challenges that genitalia must overcome for successful transfer of male gametes into the female reproductive tract. In addition, selective forces can act either on copulatory behavior and genitalia indepe...
Asymmetric genitalia and lateralized mating behaviors occur in several taxa, yet whether asymmetric morphology in one sex correlates or coevolves with lateralized mating behavior in the other sex remains largely unexplored. While lateralized mating behaviors are taxonomically widespread, among mammals they are only known in the harbor porpoise (Pho...
In species with limited opportunities for pre‐ejaculatory sexual selection (behavioral components), post‐ejaculatory mechanisms may provide opportunities for mate choice after gametes have been released. Recent evidence from a range of taxa has revealed that cryptic female choice (i.e., female‐mediated differential fertilization bias), through chem...
We evaluated whether morphological traits in capelin, Mallotus villosus, that appear to be sexually selected (pectoral fin, pelvic fin, anal fin, lateral ridge) were larger and more variable in males than females compared with naturally selected morphological traits (eyes, dorsal fin). Photographs were obtained of 136 capelin captured at two spawni...
Molecular assays of sex determination typically rely on qualitative evaluation of sex-linked markers, which can lead to uncertainty when results contradict morphological identifiers of sex. To investigate whether disagreement between phenotypic and genotypic assays of sex could be underpinned by variation in sex chromosome copy number, we developed...
Conflicting interests between the sexes to enhance their fitness potentials have resulted in several sexual strategies used by odontocetes under various social and ecological contexts. Mating tactics are diverse and non-mutually exclusive and can entail both precopulatory and postcopulatory mechanisms. Males typically rove between females, and thei...
Dolphins copulate year‐round despite short estrus periods. Copulation may be pleasurable for female dolphins through clitoral stimulation, as they have large and well‐developed clitorises. Although female mammals possess a clitoris homologous to the penis, the general structure and functional morphology has only been described in a few species. We...
Whales, dolphins, and porpoises have unusual vaginal folds of unknown function(s) that are hypothesized to play an important role in sexual selection. The potential function of vaginal folds was assessed by testing the mechanical properties of common bottlenose dolphin (Tursiops truncatus) reproductive tract tissues in 6 different regions and acros...
Sexual selection influences both genital diversity and mating behaviors, yet the integrated coevolution of pre- (behavioral) and postcopulatory (anatomical) traits in both sexes has received little attention. Traits could potentially evolve through an arms race model of escalations in male persistence and female resistance, and/or through a tradeof...
The challenges of monitoring fully aquatic and long-living mammals have limited research on cetaceans that spans several decades to only a few populations. We report the first long-term assessment of association and residency patterns of dusky dolphins (Lagenorhynchus obscurus) offKaikoura, New Zealand. Dorsal fin images, spanning 30 years of data...
The Golden Gate Bridge in San Francisco Bay provides a non-invasive aerial platform where harbor porpoises (Phocoena phocoena) can be observed mating. We photographed 144 mating events over an eight-year period (2010 to 2018) occurring in all seasons. The mating habits of free-ranging male harbor porpoises are systematically described, a first for...
Sexual selection is the primary force that drives gross morphological variation of male genitalia in many species. Less information is known about how male and female genitalia fit together during copulation or how sexual selection and mechanical constraints during copulation interact and shape reproductive organs. Marine mammals offer important in...
Sexual selection influences both genital diversity and mating behaviors, yet the integrated coevolution of pre- (behavioral) and postcopulatory (anatomical) traits in both sexes has received little attention. Traits could potentially evolve through an arms race model of escalations in male persistence and female resistance, and/or through a tradeof...
Male genital diversification is likely the result of sexual selection. Female genital diversification may also result from sexual selection, although it is less well studied and understood. Female genitalia are complex among whales, dolphins, and porpoises, especially compared to other vertebrates. The evolutionary factors affecting the diversity o...
Genitalia are morphologically variable across many taxa and in physical contact during intromission, but little is known about how variation in form correlates with function during copulation. Marine mammals offer important insights into the evolutionary forces that act on genital morphology because they have diverse genitalia and are adapted to aq...
Complex foldings of the vaginal wall are unique to some cetaceans and artiodactyls and are of unknown function(s). The patterns of vaginal length and cumulative vaginal fold length were assessed in relation to body length and to each other in a phylogenetic context to derive insights into functionality. The reproductive tracts of 59 female cetacean...
Regression of cumulative vaginal fold length on number of vaginal folds.
The non-phylogenetically controlled residuals of cumulative vaginal fold length on total body length were used. The solid black line indicates the line of best-fit from a phylogenetic reduced major axis regression (R2 = 0.113, t = 10.997, df = 19, P < 0.01).
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Counts and measurements of the specimens.
Measurements were not scaled by body length. The U.S. state (or country for New Zealand) where each specimen stranded is listed. The median is listed in parentheses when it varies from the mean.
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Cetaceans exhibit vaginal folds, unusual protrusions of the vaginal wall into the vaginal lumen. Inconsistent terminology and a lack of anatomical landmarks in the literature have hindered comparative studies of the form and function of vaginal folds. Our objectives are to: 1) develop a standardized measurement protocol for the reproductive tracts...
When males engage in scramble competition, are females non-evasive recipients of male coercion or evasive? Small groups of male dusky dolphins ( Lagenorhynchus obscurus) engage in exploitative (non-interference) scramble competition for access to oestrous females near Kaikoura, New Zealand. We conducted behavioural sequence analyses of videos of 48...
Males in polygamous species often engage in intrasexual competition for mates. If females actively evade mating attempts, it may benefit males to cooperate to restrict female movement, as has been found in some mammals. We tested if male dusky dolphins (Lagenorhynchus obscurus (Gray, 1828)) cooperate or compete during group mating chases. If they c...
Despite logistical challenges that limit direct observations of behavior for some species, physical scars can provide indirect evidence of aggression. Dusky dolphins (Lagenorhynchus obscurus (Gray, 1828)) off Kaikoura, New Zealand, derive most of the notches and scars on their dorsal fins from conspecifics. However, aggressive encounters have rarel...
AbstractBetween October 2011 and December 2013, three interactions between dusky dolphins (Lagenorhynchus obscurus) and common New Zealand octopuses (Pinnoctopus cordiformis) were witnessed and pho-tographed off Kaikoura, New Zealand. In two interac-tions, an octopus was attached to a dusky dolphin; and in a third interaction, dusky dolphins appear...
Few studies have investigated the origins of distinctive marks on cetaceans and quantitatively evaluated the causal factors. We used photo-identification data to categorize the ecological sources of scars and notches on the dorsal fins of free-ranging dusky dolphins (Lagenorhynchus obscurus) off Kaikoura, New Zealand. Dorsal fin photographs of 1,17...
In fission–fusion social systems with scramble competition between males, multiple males join mating groups while surrounding an oestrous female. If male decisions to join a mating group have been shaped by natural selection, then there should be an optimal group size resulting from the trade-offs between the benefits of monopolizing a female in sm...
Free-flying insectivorous bats occasionally collide with stationary objects they should easily detect by echolocation and avoid. Collisions often occur with lighted objects, suggesting ambient light may deleteriously affect obstacle avoidance capabilities. We tested the hypothesis that free-flying bats may orient by vision when they collide with so...
In the wild, frugivorous and nectarivorous bats often eat fermenting fruits and nectar, and thus may consume levels of ethanol that could induce inebriation. To understand if consumption of ethanol by bats alters their access to food and general survival requires examination of behavioural responses to its ingestion, as well as assessment of inters...
