As facial color pattern around the eyes has been suggested to serve various adaptive functions related to the gaze signal, we compared the patterns among 25 canid species, focusing on the gaze signal, to estimate the function of facial color pattern in these species. The facial color patterns of the studied species could be categorized into the following three types based on contrast indices relating to the gaze signal: A-type (both pupil position in the eye outline and eye position in the face are clear), B-type (only the eye position is clear), and C-type (both the pupil and eye position are unclear). A-type faces with light-colored irises were observed in most studied species of the wolf-like clade and some of the red fox-like clade. A-type faces tended to be observed in species living in family groups all year-round, whereas B-type faces tended to be seen in solo/pair-living species. The duration of gazing behavior during which the facial gaze-signal is displayed to the other individual was longest in gray wolves with typical A-type faces, of intermediate length in fennec foxes with typical B-type faces, and shortest in bush dogs with typical C-type faces. These results suggest that the facial color pattern of canid species is related to their gaze communication and that canids with A-type faces, especially gray wolves, use the gaze signal in conspecific communication.
ABSTRACT. Feces were collected from two female and one male Siberian tigers, Panthera tigris altaica. Steroid hormones were extracted from lyophilized feces and quantified by enzyme immunoassay. The fecal contents of estradiol-17β (E 2 ) and testosterone in the females and male, respectively, changed markedly throughout the year. The fecal E 2 contents of females Nos. 179 and 238 increased at 26.4 ± 8.0 and 28.0 ± 14.2 day intervals, respectively. However, the fecal contents of progesterone (P 4 ) in the female kept alone did not change. In contrast, the other female, which was kept with a male, had increased fecal P 4 contents after copulation. The fecal progesterone levels of the pregnant female remained high during her 106-day pregnancy. Reproduction in Siberian tigers, as in other Felidae, remains poor and unclear. With its restricted population, it would be a challenge for scientists to learn and familiarize themselves with the reproductive potential of Siberian tigers to improve the breeding potential of captive tigers. Gonadal steroid hormone analysis is a major point in reproduction, and assessing its changes could allow the enhancement of captive breeding programs. In the last two decades, there have been 3 reports on the endocrinology of the Siberian tiger [5,6,9].Serum hormones are the most accurate reflection of gonadal activity. Lately, some studies have shown similar patterns in serum and fecal hormones, and utilization of fecal samples as a noninvasive tool is widely used to monitor gonadal activity in farm, wild and zoo mammals [5,8]. Most steroid hormones are metabolized in the liver, discarded into urine and waste material in feces, and finally removed from the body through the defecation mechanism. A previous report indicated that in domestic cats, > 85% of progesterone (P 4 ), estradiol-17β (E 2 ), and testosterone (T) are excreted in feces [3]. It has also been reported that monitoring fecal gonadal steroid hormone changes could indicate the characteristics of gonadal activity in some Felidae species, such as cheetahs (Acinonyx jubatus), clouded leopards (Neofelis nebulosa), snow leopards (Uncia uncia), leopard cats (Felis bengalensis), and tigers [2-6, 9].The present study was undertaken to illuminate the reproductive status of Siberian tigers by assessing the changes in the fecal contents of P 4 and E 2 in female tigers and T in a male tiger.The animals monitored included a single female (Japanese Studbook No. 179, 13 years of age at the beginning of this study) housed at Yokohama Zoological Gardens, Kanagawa, Japan, and a female (No. 238, 6 years of age) and male (No. 239, 8 years of age) housed at Tama Zoological Park, Tokyo, Japan. All tigers were sexually mature based on their individual ages when this study was conducted. They were fed a diet consisting of horse meat and chicken heads.Fecal samples were collected within 18 hr after excretion once or twice a week from November 2004 to October 2005 for No. 179 and from March 2004 to June 2005 for Nos. 238 and 239. They were stored at -2...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.