Although we intelligent humans are the only survivors of the human family still living on Earth, our species was not so alone during the Ice Age. Homo sapiens lived for a time at the same time as their close hominin relatives such as Neanderthals, Homoeractus, and Denisovans. However, the last Homoeractus population became extinct in the relatively warm climate of Indonesia. This happened shortly after the advance of the last known ice age, about 100,000 years ago.
But some human relatives that faced the Ice Age were adapted to colder climates. Compared to modern humans, Neanderthals had shorter and wider bodies with short legs and wide nostrils. These features helped them retain heat in their bodies, although some scientists believe that this body type was the result of a more random genetic event rather than environmental pressure.
Neanderthals may not have been fully adapted to Ice Age climates. For example, the significant decline of the Neanderthal population around 44,000 to 40,800 years ago can be attributed to criteria such as cold and dry periods. As the surrounding environment changed, Neanderthals could not adapt in time to the pressures caused by these changes.