In order to obtain enough calories to maintain their energy and blubber supply an adult sperm whale can eat up to a ton of food per day or about 3% of its body weight. Even with teeth sperm whales are known to commonly swallow their food without biting or tearing apart the flesh of their prey and it is believed that their teeth are not necessary for their survival. The teeth on the upper jaw appear to show no use for hunting or capturing food, while the lower teeth may or may not assist with gripping onto prey. These marine mammals also possess echolocation and are born with a single blowhole, rather than two. These groups remain mostly in warm or temperate waters. In fact sperm whales have been recorded searching for foods at depths of up to 3,000 ft.