Ridgway S.H.,National Marine Mammal Foundation
Journal of the Acoustical Society of America | Year: 2011
Echolocating dolphins emit trains of clicks and receive echoes from ocean targets. They often emit each successive ranging click about 20 ms after arrival of the target echo. In echolocation, decisions must be made about the target-fish or fowl, predator or food. In the first test of dolphin auditory decision speed, three bottlenose dolphins (Tursiops truncatus) chose whistle or pulse burst responses to different auditory stimuli randomly presented without warning in rapid succession under computer control. The animals were trained to hold pressure catheters in the nasal cavity so that pressure increases required for sound production could be used to split response time (RT) into neural time and movement time. Mean RT in the youngest and fastest dolphin ranged from 175 to 213 ms when responding to tones and from 213 to 275 ms responding to pulse trains. The fastest neural times and movement times were around 60 ms. The results suggest that echolocating dolphins tune to a rhythm so that succeeding pulses in a train are produced about 20 ms over target round-trip travel time. The dolphin nervous system has evolved for rapid processing of acoustic stimuli to accommodate for the more rapid sound speed in water compared to air. © 2011 Acoustical Society of America.
Crocker D.E.,Sonoma State University |
Houser D.S.,National Marine Mammal Foundation |
Webb P.M.,University of Rhode Island
Physiological and Biochemical Zoology | Year: 2012
In capital breeders, individual differences in body size and condition can impact mating effort and success. In addition to the collateral advantages of large body size in competition, large nutrient reserves may offer advantages in endurance rivalry and enable the high rates of energy expenditure associated with mating success. We examined the impacts of body reserves and dominance rank on energy expenditure, water flux, mating success, and breeding tenure in the adult male northern elephant seal, a polygynous, capital breeder. Adult males expended energy at a rate of 195±49 MJ d -1, which is equivalent to 3.1 times the standard metabolic rate predicted by Kleiber's equation. Despite high rates of energy expenditure and a long fasting duration, males spared lean tissue effectively, deriving a mean of 7% of their metabolism from protein catabolism. Body composition had a strong impact on the ability to spare lean tissue during breeding. When controlling for body size, energy expenditure, depletion of blubber reserves, and water efflux were significantly greater in alpha males than in subordinate males. Large body size was associated with increased reproductive effort, tenure on shore, dominance rank, and reproductive success. Terrestrial locomotion and topography appeared to strongly influence energy expenditure. Comparisons with conspecific females suggest greater total seasonal reproductive effort in male northern elephant seals when controlling for the effects of body mass. In polygynous capital breeding systems, male effort may be strongly influenced by physiological state and exceed that of females. © 2012 by The University of Chicago.
Mooney T.A.,Woods Hole Oceanographic Institution |
Yamato M.,Woods Hole Oceanographic Institution |
Branstetter B.K.,National Marine Mammal Foundation
Advances in Marine Biology | Year: 2012
Sound is a primary sensory cue for most marine mammals, and this is especially true for cetaceans. To passively and actively acquire information about their environment, cetaceans have some of the most derived ears of all mammals, capable of sophisticated, sensitive hearing and auditory processing. These capabilities have developed for survival in an underwater world where sound travels five times faster than in air, and where light is quickly attenuated and often limited at depth, at night, and in murky waters. Cetacean auditory evolution has capitalized on the ubiquity of sound cues and the efficiency of underwater acoustic communication. The sense of hearing is central to cetacean sensory ecology, enabling vital behaviours such as locating prey, detecting predators, identifying conspecifics, and navigating. Increasing levels of anthropogenic ocean noise appears to influence many of these activities.Here, we describe the historical progress of investigations on cetacean hearing, with a particular focus on odontocetes and recent advancements. While this broad topic has been studied for several centuries, new technologies in the past two decades have been leveraged to improve our understanding of a wide range of taxa, including some of the most elusive species. This chapter addresses topics including how sounds are received, what sounds are detected, hearing mechanisms for complex acoustic scenes, recent anatomical and physiological studies, the potential impacts of noise, and mysticete hearing. We conclude by identifying emerging research topics and areas which require greater focus. © 2012 Elsevier Ltd.
Agency: Department of Defense | Branch: Navy | Program: STTR | Phase: Phase I | Award Amount: 80.00K | Year: 2014
Innovative Veterinary Medicine, Inc. will conceptualize and design an anesthesia ventilator named DolVent specifically designed to meet the unique physiologic requirements of Atlantic bottlenose dolphins and California sea lions. The significance of the DolVent ventilator will be its ability to properly support normal respiratory function in anesthetized animals using ventilation modes that mimic the natural breathing patterns of these animals and best manage their respiratory mechanics. To best meet these goals, DolVent will minimally include Airway Pressure Release Ventilation (APRV) and Apneustic Anesthesia Ventilation (AAV) modes. The ventilator will be designed with commercially available components and be compatible and operable with commercially available human and large animal veterinary gas anesthesia systems. The species-specific features of the DolVent ventilator will meet a modern set of biomedical criteria to maximize safety, durability and efficacy. In addition, DolVent will be fully deployable and meet compatibility/conditional standards for use in magnetic resonance imaging (MRI) facilities. A removable electronic, enhanced user interface (EUI) will be designed to improve and simplify user application of DolVent"s capabilities. A Board Certified Veterinary Anesthesiologist recognized as a global authority on anesthesia of both California sea lions and Atlantic bottlenose dolphins and will oversee concept, design, and prototype development.
Researchers follow them by drone and by sea, analyzing their waste and their exhaled breath. Now, experts want to add another layer to the exhaustive studies: individual health records for each endangered whale. The records would take existing research on the creatures and combine it in one place. The idea is to use them to monitor the orcas' health trends individually and as a population. It's similar to people having one medical record as they move from one doctor to the next or between specialists. Eighty-four orcas typically appear in Puget Sound from spring to fall. "The goal is to really start getting a lot of data and pull them together in a way that permits easier analysis," said Joe Gaydos, a wildlife veterinarian at the University of California, Davis, and chief scientist with the SeaDoc Society, which is part of the university's School of Veterinary Medicine. "Ultimately, the real benefit of any health record is to help make (management) decisions," he added. For example, if an orca appears emaciated or is in bad shape during certain times of the year, wildlife managers can access the animal's health history to see what's going on and what they could do about it, he said. Understanding the factors that affect an orca's health will ultimately help pinpoint the key threats and how to reduce them, experts say. "It will be really powerful to rule out things that aren't important and focus in on what's really important," said Lynne Barre with NOAA Fisheries. She said that will help inform research and management decisions in the long run. The project aims to pull together data on behavior, reproductive success, skin diseases and other study areas to allow for integrated analysis, she said. Scientists have enough data that they can now connect the dots to get meaningful answers, said Brad Hanson, an NOAA Fisheries wildlife biologist. More than two dozen wildlife experts met in Seattle on Tuesday to develop plans for health records for the orcas. The meeting was sponsored by SeaDoc Society, the National Oceanic and Atmospheric Administration Fisheries and the National Marine Mammal Foundation. Many details are still being worked out, including who will maintain the data and how people will access it. But an initial database would be launched this summer using readily available information, such as sex, age, gender and other details, Gaydos said. Other information would be added next year. Elsewhere, scientists have studied individual animals to monitor their health, including North Atlantic right whales. Using a database of hundreds of thousands of photographs taken over decades, researchers at the New England Aquarium and others have studied the body and skin conditions of about 400 individual right whales to assess their health. Individual Puget Sound orcas are identified by unique black and white markings or variations in their fin shapes, and each whale is given a number and a name. The Center for Whale Research on San Juan Island keeps the federal government's annual census on the population. The three families—the J, K, and L pods—are genetically and behaviorally distinct from other killer whales. They use unique calls to communicate with one another and eat salmon rather than marine mammals. Their numbers have fluctuated in recent decades as they have faced threats from pollution, lack of prey and disturbance from boats. They were listed as endangered in 2005.