The Felidae exhibits remarkable diversity in body size, with lengths ranging from 50 to 370 cm and weights from 1.1 to 423 kg. However, the underlying mechanisms driving this variation remain poorly understood. Here, we focused on the Siberian tiger (Panthera tigris altaica), the largest of the six extant tiger subspecies, and revealed the surprising expression of nicotinic acetylcholine receptors (nAChRs) in pituitary somatotrophs, which are crucial for regulating growth hormone (GH) secretion. Single-nucleus RNA sequencing of Siberian tiger pituitary cells exhibited the coexpression of CHRNA3, CHRNB4, and CHRNA5 genes in somatotrophs, a finding confirmed by electrophysiological experiments demonstrating the formation of functional nAChRs. Activation of these receptors elevated intracellular Ca²⁺ levels, thereby enhancing GH secretion in somatotrophs. Notably, nAChRs were absent in the pituitary glands of mice, domestic cats, and rats, both in early life and adulthood, despite high acetylcholine levels during early life. These results suggest that nAChRs in Siberian tiger somatotrophs play a pivotal role in GH release, offering new insights into the molecular mechanisms regulating body size in these terrestrial giants.

Geographic heterogeneity, encompassing both species‐environment interactions and interspecific relationships, significantly influences the ecological attributes of wildlife habitat selection and population distribution. However, the impact of geographic heterogeneity on the distribution of target species within predator–prey systems, particularly in human‐dominated landscapes, remains unclear. By conducting line transect surveys, utilizing a monitoring network, and applying logistic geographically weighted regression (GWR) in conjunction with generalized linear models (GLM), we examined the spatial heterogeneity of habitat selection by the Amur tiger, Amur leopard, and their main ungulate prey, wild boar and roe deer, in Northeast China. Our results suggest that the factors affecting the spatial distribution of predators are more complex than those for prey. More significantly, the selection coefficients of roe deer and wild boar for certain habitat factors serve as crucial explanatory variables in the Amur tiger and leopard models. Our findings emphasize the importance of spatial non‐stationarity in predator–prey habitat selections, and the heterogeneous selection by prey may drive dispersals of large felids across complex road landscapes. This study offers new insights into how to help apex predators cross road barriers by effectively managing prey habitat selection in a landscape dominated by roads, providing valuable guidance for future habitat conservation policies.