Scientists recently discovered that Bowhead Whales live to be over 200 years old making them the oldest mammals on earth. Some have been recently found (and killed) with 100 year old ivory spear points still in their blubber. They can live longer than us humans who, if they are American, live to almost 80 years old. This is more than elephants which can live over 70 years.
Bear in mind that our other mammal and animal friends (except the very few in captivity) take no vitamins or medicine. None go to the gym, have annual checkups or modern medical care.
See this for information on the lifespans on some other critters.