They are primarily diurnal creatures, and are carnivores. Yellowbelly Sea Snakes breed in open water when temperatures are above 20 degree C, and are ovoviviparous. They are very abundant and are not threatened or vulnerable. Oh, and have I mentioned that they are extremely venomous? The venom is actually stronger than that of a Cobra, but is administered in much smaller amounts. There have been no reported human fatalities.