Frozen Baby Mammoth, Russia

An 11-foot (3.4 m) long mammoth tusk was discovered north of Lincoln, Illinois in 2005.
Based on studies of their close relatives the modern elephants, mammoths probably had a gestation period of 22 months, resulting in a single calf being born. Their social structure was probably the same as that of African and Asian elephants, with females living in herds headed by a matriarch, whilst bulls lived solitary lives or formed loose groups after sexual maturity.