Hector's dolphins are the smallest and rarest marine dolphins in the world. They grow to be 1.2-1.5 meters long and weigh 35-60 kg. Their sides and back are light grey while their underside is whitish with black coloring on their face, fins, and tail. They are endangered due to pollution, accidental catching in fishing nets, and their slow reproduction rate of giving birth every 2-4 years.