The Irish elk is known from abundant skeletal remains which have been found in bogs in Ireland. It is thought to be distantly related to the living species currently called elk: Alces alces (the European elk, known in North America as the moose). Moose Calves can grow quickly and outrun a person by the time they are 5 days old.  A baby moose (called a calf) grows at an incredible pace during its first year of life. Calves are born in the spring, gain about one to two pounds a day, and later end up gaining five pounds a day!!

Reference: https://www.extinctanimals.org/irish-elk.htm