In 2009, 38 bowhead whales (Balaena mysticetus) were struck during the Alaskan subsistence hunt r... more In 2009, 38 bowhead whales (Balaena mysticetus) were struck during the Alaskan subsistence hunt resulting in 31 animals landed. Total landed for 2009 was a bit less than the average over the past 10 years (1999-2008: mean = 40.1; SD = 7.2). The efficiency ( # landed / # struck) of the hunt was 82%, which is about the average during 1999-2008 (mean = 78%, SD = 8%). Spring hunts are logistically more difficult than autumn hunts because of cold weather conditions and the dynamic physical challenges associated with hunting whales in sea ice. Typically, hunt efficiency during spring is lower than autumn. In 2009, however, the efficiency of the spring hunt (85%) was somewhat similar to the autumn efficiency (80%). This is likely due to the extremely difficult environmental conditions during spring 2009, which resulted in relatively few strikes at Barrow, Wainwright and Point Hope. The few strikes that were used were mostly successful. Of the landed whales, 18 were females, 12 were males, ...
In 2007, 63 bowhead whales (Balaena mysticetus) were struck during the Alaskan subsistence hunt r... more In 2007, 63 bowhead whales (Balaena mysticetus) were struck during the Alaskan subsistence hunt resulting in 41 animals landed. Total harvest for 2007 was similar to recent years. The average number of whales landed in the 10 previous years was 41.1 (SD = 7.5). The efficiency (# landed / # struck) of the hunt was 65%, which is lower than the average during 1997-2006 (mean = 79%, SD = 7%). Challenging sea ice, weather conditions, equipment malfunctions, and struck whales diving under the short-fast ice contributed to a lower efficiency in 2007 compared to the previous 10 years. These conditions especially affected hunters at Point Hope and Barrow during spring. The spring hunting efficiency was 61 % compared to 76 % for the autumn. Of the landed whales 17 were males and 24 were females. Of the 23 females of known length, 12 were presumably mature (>13.4m in length). Four of the mature females were examined closely. Of these four, three were pregnant. Biologists could not closely e...
Mammals vary dramatically in lifespan, by at least two‐orders of magnitude, but the molecular bas... more Mammals vary dramatically in lifespan, by at least two‐orders of magnitude, but the molecular basis for this difference remains largely unknown. The bowhead whale Balaena mysticetus is the longest‐lived mammal known, with an estimated maximal lifespan in excess of two hundred years. It is also one of the two largest animals and the most cold‐ adapted baleen whale species. Here, we report the first genome‐wide gene expression analyses of the bowhead whale, based on the de novo assembly of its transcriptome. Bowhead whale or cetacean‐specific changes in gene expression were identified in the liver, kidney and heart, and complemented with analyses of positively selected genes. Changes associated with altered insulin signaling and other gene expression patterns could help explain the remarkable longevity of bowhead whales as well as their adaptation to a lipid‐rich diet. The data also reveal parallels in candidate longevity adaptations of the bowhead whale, naked mole rat and Brandt’s b...
In utero, baleen whales initiate the development of several dozens of teeth in upper and lower ja... more In utero, baleen whales initiate the development of several dozens of teeth in upper and lower jaws. These tooth germs reach the bell stage and are sometimes mineralized, but toward the end of prenatal life they are resorbed and no trace remains after birth. Around the time that the germs disappear, the keratinous baleen plates start to form in the upper jaw, and these form the food-collecting mechanism. Baleen whale ancestors had two generations of teeth and never developed baleen, and the prenatal teeth of modern fetuses are usually interpreted as an evolutionary leftover. We investigated the development of teeth and baleen in bowhead whale fetuses using histological and immunohistochemical evidence. We found that upper and lower dentition initially follow similar developmental pathways. As development proceeds, upper and lower tooth germs diverge developmentally. Lower tooth germs differ along the length of the jaw, reminiscent of a heterodont dentition of cetacean ancestors, and...
The evolution of baleen constituted a major evolutionary change that made it possible for baleen ... more The evolution of baleen constituted a major evolutionary change that made it possible for baleen whales to reach enormous body sizes while filter feeding on tiny organisms and migrating over tremendous distances. Bowhead whales (Balaena mysticetus) live in the Arctic where the annual cycle of increasing and decreasing ice cover affects their habitat, prey, and migration. During the nursing period, bowheads grow rapidly; but between weaning and approximately year 5, bowhead whales display sustained baleen and head growth while limiting growth in the rest of their bodies. During this period, they withdraw resources from the skeleton, in particular the ribs, which may lose 40% of bone mass. Such dramatic changes in bones of immature mammals are rare, although fossil cetaceans between 40 and 50 million years ago show an array of rib specializations that include bone loss and are usually interpreted as related to buoyancy control.
Anatomical record (Hoboken, N.J. : 2007), Jun 24, 2016
Gross morphology and morphometry of the bowhead whale ovary, including ovulatory corpora, were in... more Gross morphology and morphometry of the bowhead whale ovary, including ovulatory corpora, were investigated in 50 whales from the Chukchi and Beaufort seas off the coast of Alaska. Using the presence of ovarian corpora to define sexual maturity, 23 sexually immature whales (7.6-14.2 m total body length) and 27 sexually mature whales (14.2-17.7 m total body length) were identified. Ovary pair weights ranged from 0.38-2.45 kg and 2.92-12.02 kg for sexually immature and sexually mature whales, respectively. In sexually mature whales, corpora lutea (CLs) and/or large corpora albicantia (CAs) projected beyond ovary surfaces. CAs became increasingly less interruptive of the surface contour as they regressed, while remaining identifiable within transverse sections of the ovarian cortex. CLs formed large globular bodies, often with a central lumen, featuring golden parenchymas enfolded within radiating fibrous cords. CAs, sometimes vesicular, featured a dense fibrous core with outward fibro...
Patterns of genetic variation observed within species reflect evolutionary histories that include... more Patterns of genetic variation observed within species reflect evolutionary histories that include signatures of past demography. Understanding the demographic component of species' history is fundamental to informed management because changes in effective population size affect response to environmental change and evolvability, the strength of genetic drift, and maintenance of genetic variability. Species experiencing anthropogenic population reductions provide valuable case studies for understanding the genetic response to demographic change because historic changes in the census size are often well documented. A classic example is the bowhead whale, Balaena mysticetus, which experienced dramatic population depletion due to commercial whaling in the late 19th and early 20th centuries. Consequently, we analyzed a large multi-marker dataset of bowhead whales using a variety of analytical methods, including extended Bayesian skyline analysis and approximate Bayesian computation, t...
Cetaceans are obligate aquatic mammals derived from terrestrial artiodactyls. The defining charac... more Cetaceans are obligate aquatic mammals derived from terrestrial artiodactyls. The defining characteristic of cetaceans is a thick and dense lip (pachyosteosclerotic involucrum) of an ear bone (the tympanic). This unique feature is absent in modern terrestrial artiodactyls and is suggested to be important in underwater hearing. Here, we investigate the mineralogical and biochemical properties of the involucrum, as these may hold clues to the aquatic adaptations of cetaceans. We compared bioapatites (enamel, dentine, cementum, and skeletal bone) of cetaceans with those of terrestrial artiodactyls and pachyosteosclerotic ribs of manatees (Sirenia). We investigated organic, carbonate, and mineral composition as well as crystal size and crystallinity index. In all studied variables, bioapatites of the cetacean involucrum were intermediate in composition and structure between those of tooth enamel on the one hand and those of dentine, cementum, and skeletal bone on the other. We also stud...
Mammals vary dramatically in lifespan, by at least two-orders of magnitude, but the molecular bas... more Mammals vary dramatically in lifespan, by at least two-orders of magnitude, but the molecular basis for this difference remains largely unknown. The bowhead whale Balaena mysticetus is the longest-lived mammal known, with an estimated maximal lifespan in excess of two hundred years. It is also one of the two largest animals and the most cold-adapted baleen whale species. Here, we report the first genome-wide gene expression analyses of the bowhead whale, based on the de novo assembly of its transcriptome. Bowhead whale or cetacean-specific changes in gene expression were identified in the liver, kidney and heart, and complemented with analyses of positively selected genes. Changes associated with altered insulin signaling and other gene expression patterns could help explain the remarkable longevity of bowhead whales as well as their adaptation to a lipid-rich diet. The data also reveal parallels in candidate longevity adaptations of the bowhead whale, naked mole rat and Brandt'...
The bowhead whale (Balaena mysticetus) is estimated to live over 200 years and is possibly the lo... more The bowhead whale (Balaena mysticetus) is estimated to live over 200 years and is possibly the longest-living mammal. These animals should possess protective molecular adaptations relevant to age-related diseases, particularly cancer. Here, we report the sequencing and comparative analysis of the bowhead whale genome and two transcriptomes from different populations. Our analysis identifies genes under positive selection and bowhead-specific mutations in genes linked to cancer and aging. In addition, we identify gene gain and loss involving genes associated with DNA repair, cell-cycle regulation, cancer, and aging. Our results expand our understanding of the evolution of mammalian longevity and suggest possible players involved in adaptive genetic changes conferring cancer resistance. We also found potentially relevant changes in genes related to additional processes, including thermoregulation, sensory perception, dietary adaptations, and immune response. Our data are made availabl...
Caribou from the Teshekpuk Herd (TH) are an important subsistence resource for residents of Inupi... more Caribou from the Teshekpuk Herd (TH) are an important subsistence resource for residents of Inupiaq villages in northern Alaska. In recent years the use of satellite telemetry has increased the understanding of the herd's annual movements and interactions with other herds. Most caribou of the TH are within the National Petroleum Reserve—Alaska (NPRA) throughout the year. The northeastern portion of NPRA has undergone two lease sales for oil and gas exploration, and lease sales are tentatively scheduled for the central/northwest portion of the NPRA in 2004. During 1990—1999, the movements of 27 caribou from the TH were tracked using satellite collars. We evaluated the proportion of time caribou were available to Inupiaq hunters by incorporating maps depicting subsistence-use areas for each of seven Inupiaq villages, and then examining seasonal and annual movements of caribou relative to those areas. By combining caribou locations with subsistence hunting areas, we were able to ex...
The use of animation clearly reveals the large annual variation in wintering areas and large diff... more The use of animation clearly reveals the large annual variation in wintering areas and large differences in daily movement rates for this herd. This interactive display can be adapted for school groups, subsistence hunters, the general public, or scientists.
In 2009, 38 bowhead whales (Balaena mysticetus) were struck during the Alaskan subsistence hunt r... more In 2009, 38 bowhead whales (Balaena mysticetus) were struck during the Alaskan subsistence hunt resulting in 31 animals landed. Total landed for 2009 was a bit less than the average over the past 10 years (1999-2008: mean = 40.1; SD = 7.2). The efficiency ( # landed / # struck) of the hunt was 82%, which is about the average during 1999-2008 (mean = 78%, SD = 8%). Spring hunts are logistically more difficult than autumn hunts because of cold weather conditions and the dynamic physical challenges associated with hunting whales in sea ice. Typically, hunt efficiency during spring is lower than autumn. In 2009, however, the efficiency of the spring hunt (85%) was somewhat similar to the autumn efficiency (80%). This is likely due to the extremely difficult environmental conditions during spring 2009, which resulted in relatively few strikes at Barrow, Wainwright and Point Hope. The few strikes that were used were mostly successful. Of the landed whales, 18 were females, 12 were males, ...
In 2007, 63 bowhead whales (Balaena mysticetus) were struck during the Alaskan subsistence hunt r... more In 2007, 63 bowhead whales (Balaena mysticetus) were struck during the Alaskan subsistence hunt resulting in 41 animals landed. Total harvest for 2007 was similar to recent years. The average number of whales landed in the 10 previous years was 41.1 (SD = 7.5). The efficiency (# landed / # struck) of the hunt was 65%, which is lower than the average during 1997-2006 (mean = 79%, SD = 7%). Challenging sea ice, weather conditions, equipment malfunctions, and struck whales diving under the short-fast ice contributed to a lower efficiency in 2007 compared to the previous 10 years. These conditions especially affected hunters at Point Hope and Barrow during spring. The spring hunting efficiency was 61 % compared to 76 % for the autumn. Of the landed whales 17 were males and 24 were females. Of the 23 females of known length, 12 were presumably mature (>13.4m in length). Four of the mature females were examined closely. Of these four, three were pregnant. Biologists could not closely e...
Mammals vary dramatically in lifespan, by at least two‐orders of magnitude, but the molecular bas... more Mammals vary dramatically in lifespan, by at least two‐orders of magnitude, but the molecular basis for this difference remains largely unknown. The bowhead whale Balaena mysticetus is the longest‐lived mammal known, with an estimated maximal lifespan in excess of two hundred years. It is also one of the two largest animals and the most cold‐ adapted baleen whale species. Here, we report the first genome‐wide gene expression analyses of the bowhead whale, based on the de novo assembly of its transcriptome. Bowhead whale or cetacean‐specific changes in gene expression were identified in the liver, kidney and heart, and complemented with analyses of positively selected genes. Changes associated with altered insulin signaling and other gene expression patterns could help explain the remarkable longevity of bowhead whales as well as their adaptation to a lipid‐rich diet. The data also reveal parallels in candidate longevity adaptations of the bowhead whale, naked mole rat and Brandt’s b...
In utero, baleen whales initiate the development of several dozens of teeth in upper and lower ja... more In utero, baleen whales initiate the development of several dozens of teeth in upper and lower jaws. These tooth germs reach the bell stage and are sometimes mineralized, but toward the end of prenatal life they are resorbed and no trace remains after birth. Around the time that the germs disappear, the keratinous baleen plates start to form in the upper jaw, and these form the food-collecting mechanism. Baleen whale ancestors had two generations of teeth and never developed baleen, and the prenatal teeth of modern fetuses are usually interpreted as an evolutionary leftover. We investigated the development of teeth and baleen in bowhead whale fetuses using histological and immunohistochemical evidence. We found that upper and lower dentition initially follow similar developmental pathways. As development proceeds, upper and lower tooth germs diverge developmentally. Lower tooth germs differ along the length of the jaw, reminiscent of a heterodont dentition of cetacean ancestors, and...
The evolution of baleen constituted a major evolutionary change that made it possible for baleen ... more The evolution of baleen constituted a major evolutionary change that made it possible for baleen whales to reach enormous body sizes while filter feeding on tiny organisms and migrating over tremendous distances. Bowhead whales (Balaena mysticetus) live in the Arctic where the annual cycle of increasing and decreasing ice cover affects their habitat, prey, and migration. During the nursing period, bowheads grow rapidly; but between weaning and approximately year 5, bowhead whales display sustained baleen and head growth while limiting growth in the rest of their bodies. During this period, they withdraw resources from the skeleton, in particular the ribs, which may lose 40% of bone mass. Such dramatic changes in bones of immature mammals are rare, although fossil cetaceans between 40 and 50 million years ago show an array of rib specializations that include bone loss and are usually interpreted as related to buoyancy control.
Anatomical record (Hoboken, N.J. : 2007), Jun 24, 2016
Gross morphology and morphometry of the bowhead whale ovary, including ovulatory corpora, were in... more Gross morphology and morphometry of the bowhead whale ovary, including ovulatory corpora, were investigated in 50 whales from the Chukchi and Beaufort seas off the coast of Alaska. Using the presence of ovarian corpora to define sexual maturity, 23 sexually immature whales (7.6-14.2 m total body length) and 27 sexually mature whales (14.2-17.7 m total body length) were identified. Ovary pair weights ranged from 0.38-2.45 kg and 2.92-12.02 kg for sexually immature and sexually mature whales, respectively. In sexually mature whales, corpora lutea (CLs) and/or large corpora albicantia (CAs) projected beyond ovary surfaces. CAs became increasingly less interruptive of the surface contour as they regressed, while remaining identifiable within transverse sections of the ovarian cortex. CLs formed large globular bodies, often with a central lumen, featuring golden parenchymas enfolded within radiating fibrous cords. CAs, sometimes vesicular, featured a dense fibrous core with outward fibro...
Patterns of genetic variation observed within species reflect evolutionary histories that include... more Patterns of genetic variation observed within species reflect evolutionary histories that include signatures of past demography. Understanding the demographic component of species' history is fundamental to informed management because changes in effective population size affect response to environmental change and evolvability, the strength of genetic drift, and maintenance of genetic variability. Species experiencing anthropogenic population reductions provide valuable case studies for understanding the genetic response to demographic change because historic changes in the census size are often well documented. A classic example is the bowhead whale, Balaena mysticetus, which experienced dramatic population depletion due to commercial whaling in the late 19th and early 20th centuries. Consequently, we analyzed a large multi-marker dataset of bowhead whales using a variety of analytical methods, including extended Bayesian skyline analysis and approximate Bayesian computation, t...
Cetaceans are obligate aquatic mammals derived from terrestrial artiodactyls. The defining charac... more Cetaceans are obligate aquatic mammals derived from terrestrial artiodactyls. The defining characteristic of cetaceans is a thick and dense lip (pachyosteosclerotic involucrum) of an ear bone (the tympanic). This unique feature is absent in modern terrestrial artiodactyls and is suggested to be important in underwater hearing. Here, we investigate the mineralogical and biochemical properties of the involucrum, as these may hold clues to the aquatic adaptations of cetaceans. We compared bioapatites (enamel, dentine, cementum, and skeletal bone) of cetaceans with those of terrestrial artiodactyls and pachyosteosclerotic ribs of manatees (Sirenia). We investigated organic, carbonate, and mineral composition as well as crystal size and crystallinity index. In all studied variables, bioapatites of the cetacean involucrum were intermediate in composition and structure between those of tooth enamel on the one hand and those of dentine, cementum, and skeletal bone on the other. We also stud...
Mammals vary dramatically in lifespan, by at least two-orders of magnitude, but the molecular bas... more Mammals vary dramatically in lifespan, by at least two-orders of magnitude, but the molecular basis for this difference remains largely unknown. The bowhead whale Balaena mysticetus is the longest-lived mammal known, with an estimated maximal lifespan in excess of two hundred years. It is also one of the two largest animals and the most cold-adapted baleen whale species. Here, we report the first genome-wide gene expression analyses of the bowhead whale, based on the de novo assembly of its transcriptome. Bowhead whale or cetacean-specific changes in gene expression were identified in the liver, kidney and heart, and complemented with analyses of positively selected genes. Changes associated with altered insulin signaling and other gene expression patterns could help explain the remarkable longevity of bowhead whales as well as their adaptation to a lipid-rich diet. The data also reveal parallels in candidate longevity adaptations of the bowhead whale, naked mole rat and Brandt'...
The bowhead whale (Balaena mysticetus) is estimated to live over 200 years and is possibly the lo... more The bowhead whale (Balaena mysticetus) is estimated to live over 200 years and is possibly the longest-living mammal. These animals should possess protective molecular adaptations relevant to age-related diseases, particularly cancer. Here, we report the sequencing and comparative analysis of the bowhead whale genome and two transcriptomes from different populations. Our analysis identifies genes under positive selection and bowhead-specific mutations in genes linked to cancer and aging. In addition, we identify gene gain and loss involving genes associated with DNA repair, cell-cycle regulation, cancer, and aging. Our results expand our understanding of the evolution of mammalian longevity and suggest possible players involved in adaptive genetic changes conferring cancer resistance. We also found potentially relevant changes in genes related to additional processes, including thermoregulation, sensory perception, dietary adaptations, and immune response. Our data are made availabl...
Caribou from the Teshekpuk Herd (TH) are an important subsistence resource for residents of Inupi... more Caribou from the Teshekpuk Herd (TH) are an important subsistence resource for residents of Inupiaq villages in northern Alaska. In recent years the use of satellite telemetry has increased the understanding of the herd's annual movements and interactions with other herds. Most caribou of the TH are within the National Petroleum Reserve—Alaska (NPRA) throughout the year. The northeastern portion of NPRA has undergone two lease sales for oil and gas exploration, and lease sales are tentatively scheduled for the central/northwest portion of the NPRA in 2004. During 1990—1999, the movements of 27 caribou from the TH were tracked using satellite collars. We evaluated the proportion of time caribou were available to Inupiaq hunters by incorporating maps depicting subsistence-use areas for each of seven Inupiaq villages, and then examining seasonal and annual movements of caribou relative to those areas. By combining caribou locations with subsistence hunting areas, we were able to ex...
The use of animation clearly reveals the large annual variation in wintering areas and large diff... more The use of animation clearly reveals the large annual variation in wintering areas and large differences in daily movement rates for this herd. This interactive display can be adapted for school groups, subsistence hunters, the general public, or scientists.
Uploads
Papers by Robert Suydam