#cavern #underwater #underwaterphotography #fareast_russia #moneronisland #blue #tunnel #light
Plantigrade vs. Digitigrade Carnivores - the Polar Bear and the African Lion
The foot structure of many animals plays a critical role in their locomotion and environmental niche, and in carnivores, the clear distinction between plantigrade (walking with the podials and metatarsals both flat on the ground) and digitigrade (walking on the toes, with the heel and wrist permanently raised) animals is most evident.
In plantigrade beasts - which include humans, many rodents, bears, racoons, and opossums - the larger surface area that the many bones provide can act as both a stabilizer and a very effective bearer of great weights. In fact, the big ol’ flighted dinosaurs were plantigrade. At the same time, so were the first (and relatively small) mammals, since both of them needed lots of stability in their feet. The weight-bearing ability and stable platform comes at the cost of speed, as the energy and requirements for movement of so many bones and muscles is much greater than digitigrade feet or unguligrade feet.
Digitigrade animals walk on only their toes, leaving their wrists and ankles permanently raised. This affords more speed, much more silent movement. Cats, birds, and dogs are digitigrade. Digitigrade feet evolved long after plantigrade feet, to fit the niche of mid-sized carnivores. However, they cannot effectively sustain large loads, which is why you cannot use a lion as a pack mule. Well, among other reasons. Really, you just don’t want to try using any mid-sized (or large, in the lion’s case) carnivore as a pack mule.
On the Anatomy of Vertebrates. Richard Owen, 1866.
(via moreanimalia)
Source: biomedicalephemera
neaq:
A giant Pacific octopus has more than 2,000 suckers spread across its eight arms, which they use for tasting, smelling, and clinging to the glass inches from your camera.
#VisitorPicture by 📷: @lllyerly #regram #octopus #giantPacificoctopus #oceananimal #NEAQtentacles #arms #newenglandaquarium #boston #massachusetts
Prowling coral colonies, the Caribbean reef octopus (Octopus briareus) is built to blend in. This camouflage artist flashes through skin textures and shades of blue, green, red and brown–allowing it to sneak up and envelop prey in a gauzy web of tentacles.
Get up close in our Tentacles exhibition
who needs space really i mean this is no doubt an alien
Octopuses freak me out
Intrigue!
Who decided this is edible…. why do people eat this?!
THERES SO MUCH GOING ON OMG
@why-animals-do-the-thing WHAT IS GOING ON HERE
The octopus is pretty much just chilling and pushing water over it’s gills via the siphon (the hole you see pulsing that tentacles poke out through at the beginning) in order to breathe. It’s a pretty vigorous motion compared to most resting/sleeping octopus I’ve seen, so I might guess it’s paying attention to something. Sometimes you can tell an octopus’ mood from skin texture or changes in color, but it tends to be very specific to each individual.
The whole ‘tentacles poking through the siphon’ thing is pretty fascinating. Octopus don’t totally have purposeful control of all of their tentacles, as far as we know. They do, however, have neurons that go all the way down each arm - it’s sort of thought each arm operates independently because of that - they don’t really check in with the central nervous system for instructions each time there’s sensory input, instead responding locally to the stimulus. The brain gives the arms high-level commands like ‘catch a fish’ or ‘pass the food to the mouth’, but the instructions for how to do so and the neural impulses required to make the details of the actions happen come from each arm. So a lot of time, the arms move pretty independently… and sometimes end up in weird places, like poking through the siphon.
@aquaristlifeforme, @thesmileoctopus, anything else to add?
This particular octopus was actually part of my thesis trials (at@aquaristlifeforme’s aquarium, actually). So. It’s not necessarily that the animal totally doesn’t know where its arms are or what they’re doing, or else they would be losing arms left and right. This behavior here is actually a very purposeful grooming of the gills and siphon, kind of the octopus equivalent of picking your nose. They shed dead skin about once a week, and rubbing their their arms (tentacles are those feeding appendages that squid and cuttlefish have) over their bodies. The GPOs in my lab in Alaska do this too!
“Octopus”
Nov 2014
#giant #octopus #korea (at Seoul, South Korea)
An octopus in the Mayotte lagoon by Gaby Barathieu
