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Sea Life, Animals
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Mexican Red-knee Tarantula

(Brachypelma smithi)

Spiders are known as arachnids; scorpions also belong to this group. Although usually peaceful, when threatened a Mexican red knee will rear up to display its fangs and the bristles on its abdomen. By rubbing its back legs, hair can be flipped as a defense. These “urticating” hairs are barbed and in contact with soft tissue they dig in and cause an irritation. Tarantulas molt usually once a year. Molting of the old exoskeleton allows the spider to grow larger, gives it a completely new set of undamaged sensory and protective hairs and also gets rid of any parasite or fungus that might have started to grow on its exterior. Lost or damaged appendages are regenerated gradually with each succeeding molt, even during the adult phase. It has eight eyes positioned around the head to see both forward and backwards. They do not have great vision, so use their sensitive leg hairs for guidance. Spiders do not hear, but they have a very well-developed ability to sense vibrations, both airborne and those transmitted through the surface on which they are standing. This sensory ability is sited in a number of different receptors on their body, but especially on the appendages.

Habitat

Primarily found on the coast and rainforests of Mexico. Found in deserts and rainforests in rocky areas, near bushes and logs and around cacti.

Diet

This species of tarantula is known to feed on insects, spiders, small lizards and small mammals. Tarantula’s ambush-hunt, generally at night. The spider will inject its prey with venom through two hollow fangs. The venom serves two purposes: first is to paralyze the victim and second is to carry digestive juices that will liquefy the insides of the prey item.

Behavior

Nocturnal and solitary. Before copulation the male takes up into his palps sperm that he has deposited on a specially spun sperm web. The sperm is then implanted in the female’s storage organs and may remain there for some time. Females lay several hundred eggs, which she covers with a sticky liquid containing the sperm. The eggs are wrapped in silk and carried between the mother’s fangs. Eggs hatch between one and a half and two and a half months. Spiderlings are guarded for several weeks.

Predators

Large birds and snakes as well as habitat destruction and the pet trade are of concern for these spiders.