Behavioral-psychological motivations encoded in the vocal repertoire of captive Amur tiger (Panthera tigris altaica) cubs

Background The Amur tiger (Panthera tigris altaica) is the largest and one of the most endangered cats in the world. In wild and captive cats, communication is mainly dependent on olfaction. However, vocal communication also plays a key role between mother and cubs during the breeding period. How cubs express their physiological and psychological needs to their mother and companions by using acoustic signals is little known and mainly hindered by the difficult process of data collection. Here, we quantitatively summarized the vocal repertoire and behavioral contexts of captive Amur tiger cubs. The aim of the present work was to investigate the behavioral motivations of cub calls by considering influential factors of age, sex, and rearing experiences. Results The 5335 high-quality calls from 65 tiger cubs were classified into nine call types (Ar-1, Ar-2, Er, eee, Chuff, Growl, Hiss, Haer, and Roar) produced in seven behavioral contexts. Except for Er, eight of the nine call types were context-specific, related to Play (Ar-2, eee, and Roar), Isolation (Ar-1), Offensive Context (Haer, Growl, and Hiss), and a friendly context (Chuff). Conclusions The results suggest that cubs are not quiet, but instead they express rich information by emitting various call types, which are probably crucial for survival in the wild. We herein provide the first detailed spectrogram classification to indicate vocal repertoires of calls and their coding with respect to behavioral contexts in Amur tiger cubs, and we pave the steps for revealing their social communication system, which can be applied for conservation of populations. These insights can help tiger managers or keepers to improve the rearing conditions by understanding the feline cubs’ inner status and needs by monitoring their vocal information expressions and exchanges.

Distinctive features of the morphometric parameters of the heart of the Amur tiger (Panthera tigris altaica) in natural habitat and in captivity

In the process of working with anatomical material supplied to the Animal Disease Diagnostic Center of the Primorskaya State Agricultural Academy, in the order of forensic examinations, a characteristic feature consisting in differences in the structure of the organs of animals living in natural habitat and in captivity was revealed. Evolutionary forces are reflected in the adaptability of animals to survive in the wild, honing adaptive characteristics and sweeping away all unnecessary things. Studying previously published works on the topic in question, it can be noted that the heart of animals in their natural habitat is slender, with a strong left side and relatively weak right side. As a rule, trabecular structures in such animals are smoothed, maximally “built” into the walls of the heart chambers. It is not often possible to find crossbeams as an element of myoendocardial formations in wild animals. However, for the internal structures of the human heart and domesticated animal species, this is not uncommon. There is an opinion that additional muscle-trabecular elements, such as: muscle crossbeams [3]; additional papillary muscles; pectinate muscles of the atria, located in a storey network - take part in the intensification of heart contractions and the creation of a swirling blood flow, providing its translational-rotational movement. This process can be considered an adaptive response to a decrease in physical activity during the evolution of a species, formed from birth to death of an organism. In the course of postmortem examinations, we examined the heart of a four-year-old female Amur tiger raised in captivity with the distinctive features of myoendocardial formations in comparison with other individuals of this species.