 Specifically, they are mammals. You know, they crawled back into the sea after many years on land. They were related to animals like hippopotamus. So their ancestors were on land, and then they crawled back into the sea. And they have mammalian brains, just like dogs, cats, and monkeys. And they happen to have some of the most intelligent ones. Orcas, incredibly intelligent, certain species of porpoise. And they have those fancy neurons I was mentioning earlier, the spindle neurons. They have those too.