Pterinochilus murinus or OBT

The P. murinus is quite infamous in the tarantula keeping hobby. Referred to by the common nickname, OBT (which can stand for “Orange Baboon Tarantula” or the slightly more colorful “Orange Bitey Thing”), this gorgeous and hardy tarantula is known for its blinding speed, potent venom and highly defensive disposition. Unlike other Ts who would rather run than throw up a threat pose, OBTs are known to stand their ground, slapping with their legs and striking in all directions when agitated.

OBTs are said to be one of the easiest tarantulas to breed and, as a result, they are quite inexpensive and common in the hobby. Most dealers carry the .5+” slings for $20 and under, and several will give out P. murinus slings as freebies. Folks who find themselves a recipient of one of these tiny, bashful chocolate brown slings will soon find themselves in possession of a bold orange ball of fury.

My P. murinus sling at about 1". Notice the chocolaty brown tones.

My P. murinus sling at about 1″. Notice the chocolaty brown tones.

Their care is quite simple, leading to some folks mistakenly (in my opinion) referring to OBTs as a good starter species. They prefer bone dry substrate and enough substrate in which to dig, and they are generally recognized as being near indestructible. I keep my three on dry coco fiber with small water dishes in the corner of the enclosure. I’ve never seen them drink, and my female especially likes to drop her boluses in her bowl.

Although this species is sometime called “semi-arboreal”, my three have constructed deep dens beneath the substrate. OBTs are normally prolific webbers, and they will often fill their cages over time with thick curtains of silk. A search on Youtube or Google will produce plenty of images and videos of industrious OBTs who have webbed up their entire enclosures. Although my sling is out most of the time, both of my juveniles have exhibited nocturnal tendencies, and I normally only see them out if I sneak down at night.

My juvenile male, about 2.75" taking a rare stroll outside of his den.

My juvenile male, about 2.75″ taking a rare stroll outside of his den.

All three of my OBTs are fantastic eaters, only refusing a meal when in premolt. In my experience, they have a medium growth rate, with frequent moltings but with less of a jump in size with each one. I purchased my sling at .5″ from Jamie’s Tarantulas in October of 2013, and it is now about 1.5″ after four molts. My juvenile pair, purchased from Arachnids RVA in December, have molted once each and are now just shy of 3″.

The sling is still quite skittish, choosing to run and hide if I so much as tap its enclosure. My juvenile female, on the other hand, has no problem throwing up a threat posture if she gets caught out in the open (see video up above!).  Still, she would much rather disappear into her burrow if afforded the opportunity. OBTs are old world tarantulas, meaning that their main defense when threatened is to bite. I don’t doubt that either of my pets would use his or her fangs if threatened.

My famale OBT standing outside of her den (it's a rarity to catch her outside)

My famale OBT standing outside of her den (it’s a rarity to catch her outside)

With its brilliant orange coloration and yellow starburst pattern on its carapace, the P. murinus is, in my opinion, easily one of the most beautiful tarantulas available. Its hearty constitution, ease of care, and availability also make for an enticing package. However, this is a fast animal, moving much more quickly than human reflexes can react to. And, being a defensive old world species, it will not hesitate to bite. A quick search of OBT bite reports should make it very apparent that this isn’t a creature you want to get tagged by. Keepers who purchase this animal because they are amused by its ornery personality and dramatic threat displays and want to show their friends are really keeping it for the wrong reason.

Although there are exceptions, most new keepers or first-time T owners would find the P. murinus to be a bit overwhelming to own. The message boards are full of posts by P. murinus owners who are terrified of their animals. Rehousings, cleanings, and feedings all have to be conducted with a great measure of care and concentration. Those new to the hobby or unaccustomed to faster-moving tarantulas could soon find themselves with a pet they are ill-equipped to deal with.

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