Search

Your search keyword '"Kohshima, Shiro"' showing total 296 results
Start Over Author "Kohshima, Shiro"
296 results on '"Kohshima, Shiro"'

12. Recent Studies on Captive Cetaceans in Japan: Working in Tandem with Studies on Cetaceans in the Wild

Author

Morisaka, Tadamichi, Kohshima, Shiro, Yoshioka, Motoi, Suzuki, Miwa, and Nakahara, Fumio

Subjects
International Journal of Comparative Psychology, Behavior, Behaviour, Communication, Vocalization, Learning, Behavioral Taxonomy, Cognition, Cognitive Processes, Intelligence, Choice, Conditioning, Language, Marine mammal, Captivity, Cetacean
Abstract

Recent technological advances have allowed researchers to acquire a vast amount of information on wild cetaceans, much of which had previously been inaccessible. However, despite these new technologies, existing studies on cetaceans in captivity remain valuable. In this article, we review the recent research conducted on captive cetaceans in Japan to show their importance. We indexed the existing studies regarding behavior (resting behavior, vocal development, social behavior, and behavior differences between species), comparative cognition (echolocation ability), stress reduction,and reproductive physiology. The resulting data, as well as an understanding of the techniques used to obtain these data, will help improve the condition of cetaceans (especially endangered species) kept in captivity and fill in the gaps of studies done on cetaceans in the wild.

Published
2010

16. Unstable environmental conditions constrain the fine-tune between opsin sensitivity and underwater light in an Amazon forest stream fish.

Author

Borghezan, Elio de Almeida, Pires, Tiago Henrique da Silva, Zuanon, Jansen, Sugiura, Hideki, Kohshima, Shiro, and Kishida, Takushi

Subjects
FRESHWATER fishes, AMINO acid sequence, GENE expression, MELANOPSIN, GENE expression profiling, VISUAL accommodation, FISH locomotion
Abstract

Visual adaptations can stem from variations in amino acid composition, chromophore utilization, and differential opsin gene expression levels, enabling individuals to adjust their light sensitivity to environmental lighting conditions. In stable environments, adaptations often involve amino acid substitutions, whereas in unstable conditions, differential gene expression may be a more relevant mechanism. Amazon forest streams present diverse underwater lighting conditions and experience short-term water colour fluctuations. In these environments, it is less likely for genetic and amino acid sequences to undergo modifications that tailor opsin proteins to the prevailing lighting conditions, particularly in species having several copies of the same gene. The sailfin tetra, Crenuchus spilurus , inhabits black and clear water Amazon forest streams. The long-wavelength sensitivity (LWS) is an important component for foraging and courtship. Here, we investigated LWS opsin genes in the sailfin tetra. Three copies of LWS1 and two copies of LWS2 genes were found. The maximum absorbance wavelength (λmax) estimated from the amino acid sequences of LWS1 genes exhibited variation among the different copies. In contrast, the copies of LWS2 genes showed identical expected λmax values. Although the amino acid positions affecting λmax varied among LWS genes, they remained consistent among populations living in different water colours. The relative expression levels of LWS genes differed between gene copies. While not formally tested, our results suggest that in fluctuating environments, visual adaptations may primarily stem from alterations in gene expression profiles and/or chromophore usage rather than precise genetic tuning of protein light sensitivity to environmental lighting conditions. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

27. Characteristics of urine spraying and scraping the ground with hind paws as scent-marking of captive cheetahs (Acinonyx jubatus)

Author

50724233, Kinoshita, Kodzue, Suzuki, Misa, Sasaki, Yuuta, Yonezawa, Aya, Kamitani, Hisayoshi, Okuda, Ryuta, Ishikawa, Tatsuya, Tsukui, Kenta, Kohshima, Shiro, 50724233, Kinoshita, Kodzue, Suzuki, Misa, Sasaki, Yuuta, Yonezawa, Aya, Kamitani, Hisayoshi, Okuda, Ryuta, Ishikawa, Tatsuya, Tsukui, Kenta, and Kohshima, Shiro

Abstract

Olfactory communication is common in felids. We observed two scent-markings, urine spraying and scraping the ground with hind paws during excretion, of 25 captive cheetahs. We analyzed the association of sniffing with the timing of urine spraying and scraping, and differences in these behaviors based on sex, age, and captive environment to understand the olfactory communication among cheetahs. Both scent-markings were strongly associated with sniffing, especially scraping, and the presence or absence of scent was thought to be a trigger. Both behaviors were observed only in adults; scraping was observed only in males. To our knowledge, this study was first to confirm the discharge of secretions from the anal glands during scraping. The frequencies of both behaviors were significantly higher in males kept in shared enclosures containing other individuals than in males kept in monopolized enclosures, while there was no difference in the frequencies among females. Female cheetahs are solitary and have non-exclusive home range, whereas male cheetahs are either solitary or live in coalition groups and there are territorial and non-territorial males. Our results could be attributed to the differences in sociality between the sexes and effect of the living environment.

Published
2022

Catalog

Books, media, physical & digital resources
See catalog results