Mysterious Sea Animals

4. Blue-ringed octopuses

Blue-ringed octopuses are among the deadliest animals in the sea. Throughout their range in Australia and the eastern Indo-Pacific, several humans suffer bites each year. Unfortunately, some of these are fatal. When alarmed, they display smaller blue rings that generally measure less than 2 mm in diameter. Two types of venom secreted by two separate venom glands are used against prey and predators. One of the venoms is used for hunting crab, the other, which is extremely toxic, is used as self defense against predators. The venoms are secreted into the blue-ringed octopus’s saliva. These bright blue rings all over its body and H. lunulata carries enough venom to kill 26 adult humans within minutes.