Family Anablepidae , Order Cyprinodontiformes , Genus Anableps . The muscles in the legs of a spider can only curl the legs, so in order to walk, a spider has to pump a fluid into its legs to uncurl them. If a spider is dehydrated, it cannot uncurl its legs and thus cannot move, with its legs all curled up. The heaviest organ in the human body is the skin, also the largest. In an adult, the skin weighs about 4 kg.
Blood is composed mainly of plasma, which is mostly water.
In an adult, blood is one 11th of the total body weight. According to recent genetic tests, the cow is closely related to the dolphin. These two animals apparently shared a common four-legged hoofed ancestor in the past. At the end of the Cretaceous period, up until the death of the dinosaurs, Triceratops was the most abundant dinosaur.