Mating and reproductive habits in snakes vary greatly depending on species and habitat. Although all snakes breathe air, sea snakes are the only water-going snakes that mate in the water. Sea snakes typically give birth to a live clutch of three or four young. Unlike terrestrial snakes who are capable of being impregnated by multiple males, sea snake females allow only one male to fertilize them.
The age of sexual maturity varies across all snake species. It depends largely on the size of the snake, its growth rate and the quality of its environment. In sea snakes, sexual maturity happens slowly. Females typically reach sexual maturity in their fourth or fifth year, males in their third.
No Seasonal Sex
Sea snakes live in tropical waters. The warm waters provide a suitable environment for mating at any point during the year. Unlike many terrestrial snakes, there is no distinct mating season as the variance in temperature in the typical sea snake environment is so small that it supports reproduction all year round. For this reason, sea snakes may not reproduce every year, although in thriving, healthy populations, reproduction may occur annually.
Sea snakes are famous for their placid, non-aggressive demeanour. However, this is only true outside of mating season. When mating urges strike, sea snakes can be quite aggressive. This aggression may be between one male and another, male and female or a snake of either sex toward another animal or person.
Nudging the Female
Prior to the act of copulation, the male will swim after the female and will use his snout to nudge her on the head or on the back of the neck. In cases where more than one male is present, the female will show preference toward her chosen male, who will then attempt to copulate with her. If another male tries to challenge, aggression may occur.
Coming Up for Air
During copulation, the male will insert one of his two penises into the cloaca. Once the penis is inserted, the male is stuck until mating is complete. It's now up to the female to decide when to come up for air. If the male fails to take in air when the female surfaces, he will have to wait until the next time. Unlike many terrestrial snakes, the male sea snake does not insert a copulation plug after mating -- most likely because there is less risk that another male will attempt to mate with the female, as the female will resist his advances.
The gestation period varies wildly, anywhere between 4 and 11 months, and is dependent on a number of factors, including abundance of food, water temperature and the age and health of the female. All sea snakes apart from the latidcaudids give birth to live young. Once born, the young are on their own; the adults have no parental instincts at all.
- Bio One: Growth and Reproduction of the Sea Snake, Emydocephalus ijimae, in the Central Ryukyus, Japan: a Mark and Recapture Study
- Australian Government; Department of the Environment: Aipysurus laevis — Olive Seasnake
- Sea Snakes: Biology
- New Scientist: True Sea Snakes Stick to One Male Only
- Sea World: Sea Snakes
Simon Foden has been a freelance writer and editor since 1999. He began his writing career after graduating with a Bachelors of Arts degree in music from Salford University. He has contributed to and written for various magazines including "K9 Magazine" and "Pet Friendly Magazine." He has also written for Dogmagazine.net.