Don't Mess With Me: The Strange Lives of Venomous Sea Creatures
BLUE-RINGED OCTOPUS Timid but Deadly In the warm tropical waters of the wide Pacific Ocean a tiny octopus its body not much bigger than a walnut creeps across a coral reef Nearby a crab armed with sharp powerful claws is ready to attack any intruder The octopus inches closer to the crab Is it sliding into a death trap Not likely The octopus brings a decisive weapon to this encounter a deadly neurotoxin neurotoxin produced by bacteria living in its salivary glands The eight-armed mollusk grabs the crustacean and bites through its shell with a bird-like beak Lethal venom seeps into the crab and shuts down its nervous system It can’t move its muscles Its fearsome claws become useless Its gills no longer absorb life-giving oxygen from seawater The octopus feasts on a fresh seafood dinner 4
A blue-ringed octopus grabs a crab dinner off Bali Indonesia DON’T MESS Timid and reclusive except when feeding the greater blue-ringed octopus glides across coral reefs in the waters of Sri Lanka Australia New Guinea Indonesia Indonesia the Philippines and southern Japan Measuring less than 8 inches 20 cm from arm tip to arm tip this little animal can kill a person with its venomous bite It eats shrimp small crabs bivalve mollusks and fish and tries to avoid being eaten by moray eels some of which appear to be immune to the toxin The colors of a blue-ringed octopus intensify with excitement as the predator reaches around a rock to attack a crab
IS THAT THING They’re Not the Same POISONOUS OR VENOMOUS Most of the 120 species of pufferfish including this star pufferfish contain the deadly nerve poison tetrodotoxin Lots of animals depend more on chemical weapons than on teeth claws speed or strength for survival but not all of them are venomous The Japanese Japanese pufferfish for example carries a powerful toxin in its liver and other organs This animal chemist is extremely poisonous and would-be predators avoid it for that reason but it is not venomous To be venomous an animal must be able to inject its toxins into other living things using spines stingers teeth or fangs Ouch 6
how nature works As in other pufferfish the nerve poison in the skin and liver of a scribbled or map pufferfish varies from season to season and place to place The toxic cocktails of most venomous sea creatures include proteins and peptides peptides small-chain proteins Some of these toxins disrupt the functioning of their victims vital nerves and muscles Others attack the circulatory system blood cells blood vessels and the heart Some cause extreme pain while others others do their damage painlessly WHY BE VENOMOUS Any trait that helps an organism live longer and reproduce more successfully is more likely to be passed down to later generations That’s how natural se lection works And acting over multiple generations natural selection causes new species to evolve Venom production has evolved in many species so it must have advantages advantages Does it require less energy than fighting fleeing or chasing Maybe so and an animal that uses less energy to survive can keep more calories in reserve to look for mates produce eggs and feed and protect its young Scientists scientists are still trying to sort out this energy equation
