Search

Your search keyword '"Orbach, Dara N."' showing total 135 results
Start Over Author "Orbach, Dara N."
135 results on '"Orbach, Dara N."'

4. Sex and Behavior

Author

Würsig, Bernd, Rich, Jacquline, Orbach, Dara N., Würsig, Bernd, editor, and Orbach, Dara N., editor

Published
2023
Full Text
View/download PDF

5. Sexual Behavior and Anatomy in Porpoises

Author

Webber, Marc A., Keener, William, Wahlberg, Magnus, Elliser, Cindy R., MacIver, Katrina, Ortiz, Sara Torres, Jakobsen, Freja, Hamel, Héloïse, Rieger, Alexandra, Siebert, Ursula, Dunn, Holly, Anderson, David, Hall, Anna M., Birdsall, Caitlin, Pielmeier, Kate, Paiu, Romulus-Marian, Boege Tobin, Deborah D., Orbach, Dara N., Würsig, Bernd, editor, and Orbach, Dara N., editor

Published
2023
Full Text
View/download PDF

8. Sex in Cetaceans

Author

Würsig, Bernd and Orbach, Dara N.

Subjects
Dolphin and Porpoise Sex and Sexual Selection, Morphologies of Cetacean Female and Male Sexual Organs, Sexual Behaviors and Strategies of Beaked Whales, Sexual Behaviors and Strategies of Harbor Porpoises, Sexual Behaviors and Strategies of Mysticetes, Sexual Behaviors and Strategies of Matriarchal Whales, Sexual Behaviors and Sexual Selection, Sexual Behaviors and Strategies of Toothed and Baleen Whales, bic Book Industry Communication::P Mathematics & science::PS Biology, life sciences::PSA Life sciences: general issues::PSAF Ecological science, the Biosphere, bic Book Industry Communication::M Medicine::MZ Veterinary medicine, bic Book Industry Communication::P Mathematics & science::PS Biology, life sciences::PSV Zoology & animal sciences, bic Book Industry Communication::P Mathematics & science::PS Biology, life sciences::PSA Life sciences: general issues::PSAJ Evolution
Abstract

Sex in Cetaceans provides an up-to-date review of multi-faceted aspects related to mating and reproduction in toothed and baleen whales. This open access book begins with discussions of sexual selection and anatomical traits related to mating and diversity between the sexes. The functions of non-conceptive copulations are reviewed as are different research techniques applied to explore sex in cetaceans. Authors and editors build knowledge of female and male social, mating, and parental strategies and tactics for several specific toothed dolphin/porpoise/whale species and baleen whale species. It concludes with a discussion of potential conservation efforts and ways to help especially beleaguered species and populations the world over. The volume is intended as a major primer of cetacean sex for undergraduate and graduate students, new and established researchers in the field, and the public wishing to learn more.

Published
2023
Full Text
View/download PDF

11. Behavioral hotspots of bottlenose dolphins in industrialized ship channels.

Author

Mills, Eliza M. M., Piwetz, Sarah, and Orbach, Dara N.

Subjects
BOTTLENOSE dolphin, MARINE mammals, MAMMAL conservation, MAMMAL behavior, MARINE habitats, MARINE resources conservation
Abstract

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 habitat use of common bottlenose dolphins (Tursiops truncatus) off Port Aransas, Texas across seasons. The relationship between behavioral states and environmental and geographical variables were analyzed. Behavioral hotspots were identified. Dolphins frequently foraged (46%), indicating the area is an important feeding ground. Dolphins also traveled (25%) and milled (22%), with less frequent occurrences of socializing (6%) and resting (1% of observations). Season, time of day, and distance to shoreline were significant predictors of foraging and traveling behavioral states. Dolphins engaged in all behavioral states closer to seawall shorelines than to mangroves and natural seagrass beds, suggesting that hard shoreline features may influence daily activity patterns. Despite daily anthropogenic operations, bottlenose dolphins use features of the industrialized area (i.e., deeply dredged channels, human-engineered seawalls) to engage in a variety of behaviors. Monitoring of dolphin behavioral states and habitat use in active ship channels are needed to assess changes from baseline data from increasing coastal development and vessel activities. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

12. Seasonal Prevalence of Skin Lesions on Dolphins across a Natural Salinity Gradient.

Author

Guinn, Makayla A., Toms, Christina N., Sinclair, Carrie, and Orbach, Dara N.

Abstract

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 ppt) in lesion development remains unknown. We assessed seasonal lesion prevalence in three free-ranging dolphin stocks inhabiting coastal Gulf of Mexico (GoM) waters of different salinities (0–30 ppt, 22–35 ppt, and 36+ ppt) using images of dolphin bodies. Lesions were documented on 44% of the dolphins photographed (n = 432), and lesion occurrence was significantly related to cold seasons and water temperatures but not salinity. Cold water temperatures may heighten dolphin susceptibility to infectious pathogens and disease and compound the effects of anthropogenic pollutants in the GoM. As dolphins are a bioindicator species of marine habitat welfare, natural studies assessing dolphin skin may reveal environmental degradation with potential impacts on marine ecosystems and human health. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

18. A deep learning approach to photo–identification demonstrates high performance on two dozen cetacean species

Author

Patton, Philip T., primary, Cheeseman, Ted, additional, Abe, Kenshin, additional, Yamaguchi, Taiki, additional, Reade, Walter, additional, Southerland, Ken, additional, Howard, Addison, additional, Oleson, Erin M., additional, Allen, Jason B., additional, Ashe, Erin, additional, Athayde, Aline, additional, Baird, Robin W., additional, Basran, Charla, additional, Cabrera, Elsa, additional, Calambokidis, John, additional, Cardoso, Júlio, additional, Carroll, Emma L., additional, Cesario, Amina, additional, Cheney, Barbara J., additional, Corsi, Enrico, additional, Currie, Jens, additional, Durban, John W., additional, Falcone, Erin A., additional, Fearnbach, Holly, additional, Flynn, Kiirsten, additional, Franklin, Trish, additional, Franklin, Wally, additional, Galletti Vernazzani, Bárbara, additional, Genov, Tilen, additional, Hill, Marie, additional, Johnston, David R., additional, Keene, Erin L., additional, Mahaffy, Sabre D., additional, McGuire, Tamara L., additional, McPherson, Liah, additional, Meyer, Catherine, additional, Michaud, Robert, additional, Miliou, Anastasia, additional, Orbach, Dara N., additional, Pearson, Heidi C., additional, Rasmussen, Marianne H., additional, Rayment, William J., additional, Rinaldi, Caroline, additional, Rinaldi, Renato, additional, Siciliano, Salvatore, additional, Stack, Stephanie, additional, Tintore, Beatriz, additional, Torres, Leigh G., additional, Towers, Jared R., additional, Trotter, Cameron, additional, Tyson Moore, Reny, additional, Weir, Caroline R., additional, Wellard, Rebecca, additional, Wells, Randall, additional, Yano, Kymberly M., additional, Zaeschmar, Jochen R., additional, and Bejder, Lars, additional

Published
2023
Full Text
View/download PDF

20. Genetic Tools to Investigate the Consequences of Sex

Author

Würsig, Bernd, Orbach, Dara N, Würsig, B ( Bernd ), Orbach, D N ( Dara N ), Gerber, Livia; https://orcid.org/0000-0002-1247-2262, Krützen, Michael; https://orcid.org/0000-0003-1055-5299, Würsig, Bernd, Orbach, Dara N, Würsig, B ( Bernd ), Orbach, D N ( Dara N ), Gerber, Livia; https://orcid.org/0000-0002-1247-2262, and Krützen, Michael; https://orcid.org/0000-0003-1055-5299

Abstract

The primary purpose of sex is reproduction. However, because not all mating events result in fertilization and only a small number of species provide biparental care to their young, successfully reproducing individuals can rarely be identified from behavioral observations alone. Genetic tools permit reliable identification of an individual’s parents and thus of successfully reproducing individuals, because each parent passes on half of their genetic material to their offspring. In cetaceans, genetic tools are required to identify a female’s already weaned offspring and to detect successfully reproducing males due to the absence of paternal care. To date, relatively few studies have investigated variables linked to reproductive success in this taxon, owed to the difficulty of sampling entire cetacean populations. We summarize currently known factors that are linked to successful reproduction in whales, porpoises, and dolphins, as well as in terrestrial mammals with comparable life histories that give birth to single young.

Published
2023

24. Contributors

Author

Acevedo-Gutiérrez, Alejandro, primary, Adam, Peter J., additional, Aguilar, Alex, additional, Amano, Masao, additional, Anderson, Paul K., additional, Archer, Frederick I., additional, Arnould, John P.Y., additional, Atkinson, Shannon, additional, Au, Whitlow W.L., additional, Aurioles-Gamboa, David, additional, Javier Aznar, F., additional, Baird, Robin W., additional, Baker, C. Scott, additional, Ballance, Lisa T., additional, Balbuena, Juan A., additional, Bannister, John L., additional, Barlow, Jay, additional, Barton, Sheri L., additional, Bearzi, Giovanni, additional, Beasley, Isabel, additional, Bekoff, Marc, additional, Ben-David, M., additional, Bengtson, John L., additional, Berta, Annalisa, additional, Bérubé, Martine, additional, Bester, Marthán N., additional, Bianucci, Giovanni, additional, Bjørge, Arne, additional, Black, Nancy A., additional, Bodkin, J.L., additional, Bonde, Robert K., additional, Borger, Jill, additional, Borrell, Asuncion, additional, Boveng, Peter, additional, Bowen, W.D., additional, Boyd, Ian L., additional, Braulik, Gillian T., additional, Brown, Alexander M., additional, Brownell, Robert L., additional, Buckland, Stephen T., additional, Burns, John J., additional, Cabrera, Andrea A., additional, Campagna, Claudio, additional, Cantor, Mauricio, additional, Cárdenas-Alayza, Susana, additional, Cárdenas-Hinojosa, Gustavo, additional, Castellini, Michael, additional, Cerchio, Salvatore, additional, Champagne, Cory D., additional, Chilvers, B. Louise, additional, Chivers, Susan J., additional, Cipriano, Frank, additional, Clapham, Phillip J., additional, Constantine, Rochelle, additional, Cooper, Lisa N., additional, Corkeron, Peter, additional, Costa, Daniel P., additional, Costidis, Alexander M., additional, Cowan, Daniel F., additional, Cranford, Ted, additional, Crespo, Enrique A., additional, Crocker, Daniel E., additional, Croll, Donald A., additional, da Silva, Vera M.F., additional, Danil, Kerri, additional, Darling, Jim, additional, Dawson, Stephen M., additional, de Muizon, Christian, additional, de Vos, Asha, additional, Dehnhardt, Guido, additional, DeMaster, Douglas P., additional, Deméré, Thomas A., additional, Dendrinos, Panagiotis, additional, Dill, Lawrence M., additional, Dizon, Andrew E., additional, L. Dolar, M. Louella, additional, Domning, Daryl P., additional, Donovan, G.P., additional, Dudzinski, Kathleen M., additional, Duffield, Deborah A., additional, Dyer, Michael P., additional, Ellis, Richard, additional, Eskelinen, Holli, additional, Estes, James A., additional, Evans, Peter G.H., additional, Fernández, Mercedes, additional, Fertl, Dagmar, additional, Fettuccia, Daniela de Castro, additional, Fiedler, Paul C., additional, Fish, Frank E., additional, Flores, Paulo A.C., additional, Forcada, Jaume, additional, Ford, John K.B., additional, Fordyce, R. Ewan, additional, Forestell, Paul H., additional, Forney, Karin A., additional, Fowler, Charles W., additional, Frankel, Adam S., additional, Friedlaender, Ari S., additional, Frohoff, Toni, additional, Frost, Kathryn J., additional, Galatius, Anders, additional, García-Vernet, Raquel, additional, Geisler, Jonathan H., additional, Gelatt, Thomas S., additional, Gentry, Roger, additional, George, J. Craig, additional, Gerrodette, Tim, additional, Goldbogen, Jeremy A., additional, Goldsworthy, Simon D., additional, P. Goodall, R. Natalie, additional, Goodman, Simon J., additional, Gregg, Justin D., additional, Hall, Ailsa J., additional, Hammill, Mike O., additional, Hammond, Philip S., additional, Hanke, Frederike D., additional, Hartman, Karin L., additional, Hazen, Elliott, additional, Heide-Jørgensen, M.P., additional, Heithaus, Michael R., additional, Herman, Louis M., additional, Herzing, Denise L., additional, Hewitt, Roger P., additional, Hindell, Mark A., additional, Hoelzel, A. Rus, additional, Hofmeyr, G. J. Greg, additional, Hohn, Aleta A., additional, Hooker, Sascha K., additional, Horstmann, Lara, additional, Horwood, Joseph, additional, Hoyt, Erich, additional, Hückstädt, Luis A., additional, Ivashchenko, Yulia V., additional, Iverson, Sara J., additional, Janik, Vincent M., additional, Jaramillo-Legorreta, Armando M., additional, Jefferson, Thomas A., additional, Jensen, Anne M., additional, Karamanlidis, Alexandros A., additional, Kasuya, Toshio, additional, Kato, Hidehiro, additional, Keith Diagne, Lucy W., additional, Kemp, Christopher, additional, Kemper, Catherine M., additional, Kenney, Robert D., additional, Kinze, Carl C., additional, Kirkman, Stephen P., additional, Kiszka, Jeremy J., additional, Koopman, Heather N., additional, Kooyman, Gerald L., additional, Kovacs, Kit M., additional, Kraus, Scott D., additional, Krysl, Petr, additional, Laidre, Kristin L., additional, Laitman, Jeffrey T., additional, Lambert, Olivier, additional, Landry, André M., additional, Lavigne, David M., additional, LeDuc, Rick, additional, Lipsky, Jessica D., additional, Littnan, Charles, additional, Loughlin, Thomas R., additional, Lowry, Lloyd, additional, Lowther, Andrew D., additional, Lydersen, Christian, additional, Maas, Mary C., additional, MacLean, Stephen A., additional, MacLeod, Colin D., additional, Mallette, Sarah D., additional, Mann, Janet, additional, Maresh, Jennifer L., additional, Marsh, Helene, additional, Marshall, Christopher D., additional, Martin, Anthony R., additional, Mass, Alla M., additional, McAlpine, Donald F., additional, Chris McKnight, J., additional, McLellan, William A., additional, Mead, James G., additional, Melin, Sharon R., additional, Merrick, Richard, additional, Mesnick, Sarah L., additional, Miller, Edward H., additional, Miller, Lance J., additional, Miller, Patrick J.O., additional, Miyazaki, Nobuyuki, additional, Moore, Jeffrey E., additional, Moore, Kathleen M., additional, Moore, Michael, additional, Moore, Sue E., additional, Moors-Murphy, Hilary B., additional, Morin, Phillip A., additional, Newman, William A., additional, Newton, Kelly M., additional, Nieto-García, Edwyna, additional, Northridge, Simon, additional, Nummela, Sirpa, additional, O'Brien, Justine K., additional, O'Corry-Crowe, Gregory M., additional, Olsen, Morten T., additional, Olson, Paula A., additional, Oppenheimer, Jonas, additional, Orbach, Dara N., additional, Ortiz, Rudy M., additional, Pabst, D. Ann, additional, Palsbøll, Per J., additional, Parra, Guido J., additional, Patterson, Eric, additional, Paves-Hernández, Héctor, additional, Perrin, William F., additional, Perryman, Wayne L., additional, Pitman, Robert, additional, Pomeroy, Patrick P., additional, Ponganis, Paul J., additional, Powell, James A., additional, Pyenson, Nicholas D., additional, Racicot, Rachel, additional, Raga, J. Antonio, additional, Ralls, Katherine, additional, Raverty, Stephen, additional, Read, Andrew J., additional, Reeves, Randall R., additional, Regehr, Eric V., additional, Reggente, Melissa A.L., additional, Reidenberg, Joy S., additional, Reijnders, Peter J.H., additional, Reyes, Julio C., additional, Reynolds, John E., additional, Robeck, Todd R., additional, Robinson, Kelly J., additional, Rode, Karyn, additional, Rogers, Tracey, additional, Rojas-Bracho, Lorenzo, additional, Roman, Joe, additional, Rommel, Sentiel A., additional, Roos, Marjoleine M.H., additional, Rosel, Patricia E., additional, Rowntree, Victoria J., additional, Rugh, David, additional, Russell, Debbie J.F., additional, Sayigh, Laela S., additional, Scolardi, Kerri M., additional, Scott, Michael D., additional, Sears, Richard, additional, Seger, Jon, additional, Sharp, Sarah, additional, Sheehan, Glenn W., additional, Silber, Gregory K., additional, Simeone, Claire A., additional, Smith, Brian D., additional, Southall, Brandon L., additional, Spitz, Jérôme, additional, Spoor, Fred, additional, Stacey, Rita, additional, Staniland, Iain J., additional, Steel, Debbie, additional, Stern, S. Jonathan, additional, Stewart, Brent S., additional, Supin, Alexander Y., additional, Suydam, R., additional, Swartz, Steven L., additional, Teilmann, Jonas, additional, Tershy, Bernie R., additional, Thewissen, J.G.M., additional, Tinker, M.T., additional, Tolley, Krystal A., additional, Trillmich, Fritz, additional, Trites, Andrew W., additional, Turner, Ted, additional, Twiss, Sean D., additional, Tyack, Peter L., additional, Uhen, Mark D., additional, Van Franeker, Jan A., additional, Van Waerebeek, Koen, additional, Wade, Paul R., additional, Wang, John Y., additional, Weller, David W., additional, Wells, Randall S., additional, Werth, Alexander J., additional, Whitehead, Hal, additional, Williams, Terrie M., additional, Würsig, Bernd, additional, Yablokov, Alexey V., additional, Yamada, Tadasu K., additional, Yamato, Maya, additional, Yochem, Pamela K., additional, York, Anne E., additional, and Zhou, Kaiya, additional

Published
2018
Full Text
View/download PDF

28. Salinity Affects Wound Healing in Wild Common Bottlenose Dolphins (Tursiops truncatus).

Author

Hurst, Brianna and Orbach, Dara N.

Subjects
BOTTLENOSE dolphin, WOUND healing, SALINITY, HEALING, DOLPHINS, SCARS
Abstract

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 Texas contains the only hypersaline lagoon in the USA, located adjacent to hyposaline waters, with genetically distinct populations of dolphins in the two environments. Photographs of dolphin dorsal fins were collected, and scar stability over time was determined and compared by measuring changes in the relative lengths and surfaces of scars. All scars on dolphins in the hypersaline lagoon completely diminished between three to six years, while scars on dolphins in the hyposaline bay ranged in the amount of fading between three to six years. Data from this case study indicate that high salinity may increase the healing speed of wounds on common bottlenose dolphins compared to low salinity, although a larger sample size is needed for robust statistical comparison. Scar diminishment is an important consideration in determining the temporal reliability of photo identification. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

30. Drag reduction and locomotory power in dolphins: Gray’s paradox revealed

Author

Davis, Randall W., Fiori, Lorenzo, Würsig, Bernd, and Orbach, Dara N.

Abstract

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 physiologically impossible. Using an uncrewed aerial vehicle, we calculated the total power of free-ranging dusky dolphins (Lagenorhynchus obscurus) at speeds from 0.9 to 6.9 m s−1, deriving drag coefficients (Cd) and drag. Our results showed that the Cddecreased exponentially with speed, reducing drag by up to 89% at speeds >2 m s−1, with an additional 17% reduction during porpoising (>4.0 m s−1). At 6.9 m s−1, drag was 32 N, with a power of 15.8 W kg−1, nearly identical to the mass-specificallometric prediction for the maximum aerobic capacity of other mammals and physiologically possible. The Cdat speeds >2.5 m s−1indicated reduced turbulence in the boundary layer around the dolphin’s body, thereby reducing drag. The ability of dusky dolphins to swim at sustained high speeds resulted from an exponential decrease in Cd, which was further reduced by porpoising, thereby explaining the low drag and locomotory power that resolved Gray’s paradox.

Published
2024
Full Text
View/download PDF

35. Contributors

Author

Banerjee, Arnab, Bateman, Helen L., Bautista, Anna Isabel, Beery, Annaliese K., Butler, Chloe E., Cain, Joe W., Charapata, Patrick, Chiang, Vic Shao-Chih, Chung, Wilson C.J., Curry, Erin, Flaws, Jodi A., Fletcher, Endia J., Guinn, Makayla, Harris, Breanna N., Herrick, Jason R., Hodgson, Mitchell J., Hood, Wendy R., Huhtaniemi, I., Inman, Zane, Itakura, Takumi, Jenkin, Graham, Johnson, Gregory A., Josefson, Chloe C., Krishna, Amitabh, Larson, Ashley M., Laws, Mary J., Lee, Nicole S., Lefevre, Carli, Lopez, Kristin H., McAllan, Bronwyn M., McCarthy, Margaret M., Mesiano, Sam, Mourikes, Vasiliki, Nagashima, Jennifer B., Neff, Alison M., Norris, David O., Orbach, Dara N., Orr, Teri J., Pak, Toni R., Papadopoulos, V., Park, Jin Ho, Pathirana, Dineth M., Renfree, Marilyn B., Ross, Alex, Roy, Vikas Kumar, Rutherford, Julienne N., Saltzman, Wendy, Santacruz-Márquez, Ramsés, Shaw, Geoff, Skibiel, Amy L., Smith, Roger, Songsasen, Nucharin, Sperou, Emily S., Tardif, Suzette D., Touhara, Kazushige, Whittington, Camilla M., Wilsterman, Kathryn, Young, I. Ross, and Zirkin, B.

Published
2024
Full Text
View/download PDF

39. Table S2: 3-D model fit of males inside females. from Genital interactions during simulated copulation among marine mammals

Author

Orbach, Dara N., Kelly, Diane A., Solano, Mauricio, and Brennan, Patricia L. R.

Abstract

Results show the best fit at 0 degrees, and subsequent rotation of the male inside the female at 90, 180, and 270 degrees. As the model is rotated, the percentage of models not overlapping increases within each species. F-M describes the volume of the female left unfilled by the male and M-F describes the volume of the male not encapsulated by the female.

Published
2017
Full Text
View/download PDF

40. Table S1: Length of endocasts and penis tips in four species of marine mammals. from Genital interactions during simulated copulation among marine mammals

Author

Orbach, Dara N., Kelly, Diane A., Solano, Mauricio, and Brennan, Patricia L. R.

Abstract

Penis lengths were collected after inflation but prior to formalin-fixation. Penises were measured from the cranial point of fusion of the sheath to the shaft through to the cranial (distal) tip of the penis. Endocast and penis length measurements were collected in ventral, dorsal, left lateral, and right lateral orientations. The longest length is presented due to asymmetries in shape.

Published
2017
Full Text
View/download PDF

43. Sexually selected traits are larger and more variable in male than female beach‐spawning capelin, Mallotus villosus.

Author

Orbach, Dara N., Donovan, Meghan, and Purchase, Craig F.

Subjects
*BODY size, *PECTORAL fins, *FISH spawning, *SPAWNING, *SEXUAL dimorphism, *PHYSICAL contact
Abstract

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 spawning sites and standardised measurements were taken of six morphological traits. Males had larger traits than females for a given body size and this was most pronounced in the traits thought to be sexually selected. Body size explained much of the variation in female traits but less variation in male traits, suggesting alternative selection pressures are involved. We suggest that larger male body size aids in endurance rivalry and sexually dimorphic traits help males to remain in physical contact with females while spawning on the beach. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

49. Armed Escorts: Dusky Dolphin (Lagenorhynchus obscurus) Interactions with Octopuses (Pinnoctopus cordiformis) in New Zealand.

Author

Orbach, Dara N. and Kirchner, Theresa

Subjects
*DUSKY dolphin, *OCTOPUSES, *AQUATIC mammals, *MAMMAL ecology, *MARINE mammalogy, *BEHAVIOR
Abstract

Between October 2011 and December 2013, three interactions between dusky dolphins (Lagenorhynchus obscurus) and common New Zealand octopuses (Pinnoctopus cordiformis) were witnessed and photographed off Kaikoura, New Zealand. In two interactions, an octopus was attached to a dusky dolphin; and in a third interaction, dusky dolphins appeared to be playing with an octopus. The attachment might have been an escape tactic for the octopuses. This is the first published record of interactions between dusky dolphins and octopuses in New Zealand. The few anecdotal reports of octopuses attached to dolphins are limited to species that commonly prey on octopuses. The evidence for dusky dolphins foraging on octopuses off Kaikoura is weak. The two species have different habitats but could come into initial contact through shallow nearshore dives performed by the dusky dolphins or by other species observed in the area, including New Zealand fur seals (Arctocephalus forsteri), humpback whales (Megaptera novaeangliae), or fishermen retrieving craypots. When the dusky dolphins encountered this unusual object in their environment, they may have initiated exploratory or playful behavior, which changed to distressed or defensive behavior upon the attachment of the octopuses. The erratic behaviors of the dolphins, including tail thrashes, rolling over, and rapid changes in swimming speed and direction, indicate they were disturbed by the presence of the affixed octopus. The dolphins did not perform acrobatic leaps, which are predicted to remove or reposition large "hitchhikers." [ABSTRACT FROM AUTHOR]

Published
2014
Full Text
View/download PDF

50. Sources of Notch and Scar Patterns on the Dorsal Fins of Dusky Dolphins (Lagenorhynchus obscurus).

Author

Kügler, Anke and Orbach, Dara N.

Subjects
*FINS (Anatomy), *DUSKY dolphin, *SCARS, *AQUATIC mammals, *MARINE mammalogy, PHOTOIDENTIFICATION of animals
Abstract

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 freeranging dusky dolphins (Lagenorhynchus obscurus) off Kaikoura, New Zealand. Dorsal fin photographs of 1,171 individuals that had marks from ecological sources were collected from October 2011 through January 2012. Photographs of scars and notches were compared to marks of known origin, cross-validated by experts, and categorized as derived from conspecifics, killer whales, sharks, vessel strikes, fishing gear, or unknown. A total of 1,019 dusky dolphins had notches, of which 419 (41%) individuals had additional scars. A smaller subset of dolphins (152 individuals) had only scars or pigmentations as marks. The marks on the majority of dusky dolphins were attributed to intraspecific interactions (notches: 84%, n = 983; scars: 30%, n = 355). Indications of predation attempts (sharks: 0.17%, n = 2; killer whales: 0.09%, n = 1; unclassified natural predators: 0.26%, n = 3) and human impact (net/line: 0.43%, n = 4; vessel: 0.17, n = 2; unclassified human impact: 0.34%, n = 4) were comparatively low. These results are consistent with previous studies and indicate that most marks on dusky dolphins are caused by conspecifics and that predation pressure and bycatch rates are low off Kaikoura. We suggest that these data indicate that current management actions regulating commercial and recreational boating activities in the area are sufficient, with no need for immediate modification. [ABSTRACT FROM AUTHOR]

Published
2014
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results