摘要:

AbstractGrowth layers were examined in teeth collected from free‐ranging bottlenose dolphins, Tursiops truncatus, from Florida that have been part of a long‐term study begun in 1970; 26 of the dolphins were of known or approximately known age, and 19 were of minimum known age. A second tooth was extracted from 6 animals for examination of growth that had taken place in the interval following the initial extraction. The teeth were read for age estimates without knowledge of any data pertaining to the animals. Most of the estimated ages were the same as or close to the known and approximately known ages of the animals, ranging from 2 to 16 yr. We conclude that the structures we define as dentinal growth layer groups (GLGs) are annual, we describe sources of error in age estimates, and we provide a description of the GLG pattern that can be used by others to estimate age for dolph

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1989.tb00346.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe phylogenetic relationships of the major groups of pinnipeds are of longstanding controversy. According to prevailing paleontological opinion, pinnipeds comprise two distinct lineages of independent terrestrial carnivoran origin, A logical correlate of this view is that an enormous degree of convergence accounts for the striking resemblances of these groups.It has been generally supposed that derived similarities common to pinnipeds are independently acquired adaptations to a highly constraining environment. This has not been adequately substantiated. Moreover, considerable evidence favors a contrary conclusion. Acceptance of convergence necessarily rests on demonstration that taxa possessing characters suspected to be convergent are in fact not mutal nearest allies. In the absence of such phylogenetic information, shared derived characters are indicative of common ancestry irrespective of whether they are deemed “functionally important.” Given meager support for the proposition that pinnipeds are related to different terrestrial lineages, it is currently more judicious to regard the group's origin as monophyletic. In addition to the presumed prevalence of convergence, biogeography, the high degree of morphological divergence of phocids, and the aberrant nature of phocines have improperly contributed to acceptance of independent pinniped orig

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1989.tb00347.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractWe tested a satellite Platform Transmitter Terminal (PTT) in the laboratory (on a float and on captive seals) and on a free‐ranging harbor seal in the Southern California Bight to investigate the utility of satellite telemetry in documenting seals’at‐sea behavior and movements. We used records from a microprocessor‐based time‐depth recorder (TDR) to interpret location and diving records from the PTT. For the free‐ranging harbor seal, we obtained at least one uplink during 70% (while the seal was at sea) to 82% (while she was ashore) of satellite passes and at least one location each day. Of 62 locations determined by Service Argos for the free‐ranging seal, 20 were verified from TDR records to have been at sea; these indicated that the seal may have ranged up to 48 km from the haul‐out site, although most locations were within 5 km. The accuracies of locations calculated when the seal was at sea (±15 km) were substantially less than when it was ashore (±1.5 km), thus limiting at‐sea tracking of seals by satellite to rather gross movements. Fewer transmissions were detected and locations calculated when the seal was actively diving than when it was swimming near the surface as it departed from or returned to the haul‐out site. Consequently, average dive durations indicated by the PTT were substantially shorter than those calculated from TDR records. Documentation of foraging areas and detailed at‐sea movements using satellite technology may not be possible for pinnipeds unless PTT‐transmission rates are increased substantially from the 1 per 45 set maximum rate now p

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1989.tb00348.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractA small intraperitoneal radio transmitter was developed and used successfully in California sea otters. The transmitter weighs about 120 g and has an internal antenna. Thirty‐five implanted transmitters were located for an average of 526 d. The carcasses of five animals that died were recovered; there were no complications associated with the transmitters in these individuals. Reproductive performance of the adult females with implanted transmitters appeared normal. The main advantages of this transmitter are its reliability and long life. It has enabled the collection of significant new information on California sea otter

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1989.tb00349.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1989.tb00350.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1989.tb00351.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1989.tb00352.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1989.tb00353.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1989.tb00354.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Biologyof the GenusCephalorhynchus.R. L. Brownell, Jr. and G. P. Donovan, eds.WhalesoftheWorld. N. Bonner.MarineMammalsofCaliforniaNew and revised edition. R. T. Orr and R. C. Helm.

ISSN:0824-0469    

DOI:10.1111/j.1748-7692.1989.tb00355.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY