Do sperm whales eat sharks?

The sperm whales feed on several species, notably the giant squid, but also the colossal squid, octopuses, and fish like demersal rays. Some prey may be taken accidentally while eating other items. Most cetaceans have throats that are too small to swallow a shark; but the sperm whale is an exception. They have been known to eat the megamouth shark and there is evidence of their having eaten a great white shark.

Here is some interesting information for you:

A sperm whale is the largest ocean carnivore. It is the largest of the toothed whale species in the world: adult males can grow up to 20 metres long and weigh 40 tonnes. Sperm whales usually dive between 300 to 800 metres -- sometimes 1 to 2 kilometres - in search of food and such dives can last more than an hour.