 Unlike other baleen whales, "Janjucetus" did not use baleen to filter feed, and instead used teeth to catch large prey such as fish and sharks.Its skull morphology seems to be convergent with the modern-day leopard seal ("Hydrurga leptonyx"), and so it may have used a similar grip-and-tear feeding method.However, it is possible that the front teeth interlocked, and the cheek teethed sheared against each other when the mouth was closed, which perhaps allowed the whale to filter feed similar to the modern day crabeater seal ("Lobodon carcinophaga").