As of 2015, some animals that have become extinct within the past 100 years include the golden toad, the Pinta Island tortoise and the Caspian tiger. Although none of these animals exist as separate populations, their genetics, in some cases, live on within related subspecies.
The golden toad was once a common animal throughout its range in Costa Rica, and its breeding sites were well-known, allowing scientists to reliably monitor the species' population. However, by 1988, there were only a handful of breeding pairs left. Since 1989, it is considered extinct.
The Pinta Island tortoise was declared extinct in 2012. The last surviving animal was named Lonesome George and had been part of an ultimately unsuccessful breeding program that began in the 1970s.
The Caspian tiger was last sighted in the wild in the early 1970s. It is considered extinct, but scientists are hopeful that the subspecies can be reintroduced to the Caspian Sea region, due to its close genetic relationship with the living Amur subspecies. Amur and Caspian tigers are so closely related that some consider them the same subspecies.