Vampire squid, whose scientific name is
Vampyroteuthis infernalis, are a deep-water species that reside in ocean depths from 500 to 3,000 meters. They are passive, soft-bodied animals with a dark red body, huge blue eyes, and a cloak-like web that stretches between its eight arms. Vampire squid have very different feeding and reproductive strategies than all other cephalopod species.
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| Figure 1. A vampire squid with its cloak-like webs visible |
Typically, squids and octopuses eat live prey, but a 2012 study by Hoving and Robison showed that this is not the case for vampire squid. The researchers showed that vampire squid mostly eat “marine snow” which sinks to the deep-sea from the higher depths of the ocean. Marine snow is a mixture of the remains of microscopic algae and animals, fecal pellets from copepods or krill, and debris from gelatinous larvaceans. The vampire squid eat the marine snow by catching food particles on string-like filaments, drawing the filament through its arms, removing the particles and enveloping them in mucus, then transferring the mucus and particles to its mouth.
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| Figure 2. A vampire squid surrounded by marine snow |
Although this is a very low energy diet, it is able to sustain the vampire squid for several reasons. Vampire squid are neutrally buoyant, and they don’t have to swim to find food since they can just extend their filaments to collect food from the water. For these reasons, the squids have to expend very little energy to stay at a certain depth and feed. Also, vampire squid don’t have to expend energy to avoid predators. This is because there is very little oxygen in the deep-sea, so very few animals can survive, leading to less predators.
In addition, the reproductive strategy of the vampire squid differs from all other coleoid cephalopods. All other cephalopods reproduce all at once later in their lives in one big reproductive event. The low energy lifestyle of the vampire squid, however, does not support this kind of energy expenditure. Rather, vampire squid alternate between reproductive and resting phases, which is a pattern more common among fish. The squid release about 100 eggs per spawning event for around 100 or so spawning events. These unique characteristics of the vampire squid show how different deep sea-dwelling creatures can adapt and indicate how little is known about the deep-sea.
References:
Cell Press. (2015, April 20). Vampire squid discovery shows how little we know of the deep sea. ScienceDaily. Retrieved March 2, 2018 from www.sciencedaily.com/releases/2015/04/150420122828.htm
Monterey Bay Aquarium Research Institute. (2012, September 26). Researchers discover what vampire squids eat: It's not what you think. ScienceDaily. Retrieved March 2, 2018 from www.sciencedaily.com/releases/2012/09/120926133239.htm
I enjoyed your post! The vampire squid has to have unique traits to lives at the depths they do. I would be curios to know how the squid cope with the little oxygen at the depth level they live at.
ReplyDeleteThis species of vampire squid is the only known surviving member of its order. This squid is able to live and breathe normally in the minimum zone at oxygen saturations as low as 3%, an ability that few other animals possess. This is an incredible adaptation. Of all deep-sea cephalopods, their mass-specific metabolic rate, according to a source I looked into, is the lowest. Their blue blood's hemocyanin binds and transports oxygen more efficiently than in other cephalopods. The surface area of their gills is much higher, which allows a higher intake of oxygen. The squid also have a weak musculature, yet they still maintain agility and buoyancy with little effort because of sophisticated statocysts (balancing organs similar to a person's inner ear) and ammonium-rich gelatinous tissues closely matching the density of the surrounding seawater. They quite simply are amazing creatures.
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