スミソニアン国立動物園さんのインスタグラム写真 - (スミソニアン国立動物園Instagram)「🦁Lion cubs grow up fast, and even faster in zoos. In a long-term study, scientists at the Smithsonian Conservation Biology Institute found male African lions living in human care hit puberty a full year earlier than their counterparts in the wild. As the population of lions in the wild continues to shrink due to habitat loss, conflict with humans and disease, knowing exactly when male lions reach puberty and are capable of breeding is important for conserving the species. In the wild, male lions start experiencing a rise in testosterone at approximately 2 years old, which signals that the male is becoming sexually mature and it is time for him to leave the pride and search for mates. Male zoo lions start producing the hormone around 1 year old, a full year before wild males. Researchers confirmed that the males had reached puberty by looking for sperm in the urine, which was also present starting around 1 year old. Despite reaching puberty earlier, many zoo-born male lions live with the pride they were born into until they are approximately 3 years old. The research shows that zoos should consider separating male lions from their birth prides at an earlier age and pair them with unrelated females to establish their own prides. The authors speculate that one reason why male lions living in zoos are hitting puberty earlier is because they are growing and gaining weight faster. Wild cubs often go through long periods without food, especially after they are weaned and must transition to eating meat. By contrast, lion cubs born in zoos have a constant supply of nutritious food and are not dependent on their parents to hunt for it. There are about 20,000 lions living in Africa and their numbers have declined by 30% in the past decade. Their habitats are increasingly fragmented and isolated, putting the species at risk of becoming inbred in the wild and susceptible to disease. There are 750 lions living in zoos around the world and breeding those lions to create a genetically healthy population in human care is increasingly important for the survival of the species as a whole. #Lions #AfricanLion #WeSaveSpecies」7月4日 3時35分