Socotra Island Blue Baboon Tarantula (Monocentropus balfouri) Care Sheet

Scientific Name: Monocentropus balfouri

Common Name: Socotra Island Blue Baboon

Type: Terrestrial Opportunistic Burrower

Category: Old World

Endemic Location: Socotra Island off the coast of Yemen

Body Length: 2.5” (7cm)

Diagonal Leg Span (DLS): 7” (18cm)

Urticating Hairs: No

Growth Rate: Slow

Life Expectancy: Females 12-14 years / Males 3-4 years

Recommended Experience Level: Intermediate

The Monocentropus balfouri known commonly in the hobby as the Socotra Island Blue Baboon was described by Pocock in 1897 and is an Old World Terrestrial species that is native to the island of Socotra about 150 miles east of the horn of Africa. This area has a tropical to semi desert climate with fairly moderate temperatures and rainfall. Being from this island and secluded, this species has evolved in ways unlike other tarantulas. First they have a very identifiable color pattern that makes them very recognizable. Also they are known as the most communal tarantula in the hobby as they have naturally evolved into living in close quarters in their natural habitat. Though they haven't been witnessed living communally in the wild, they are one of a very few species of tarantulas that can live communally in captivity. This species has a medium growth rate with females reaching a maximum diagonal leg span of 5-6” within a few years while males are a little bit smaller. There is some sexual dimorphism in this species but it is not the most reliable way to determine the sex of your specimen. The best way to know if you have a male or female is to examine the inside of a molt. But some have reported that once a male has its ultimate molt and is fully mature and ready to mate, its carapace will be bright blue while females will be grey or lighter blue. The reason this isn't the best method is that I have seen many reports on line from those with first hand knowledge saying their males never developed the bright blue carapace upon maturing. These spiders have a fairly mellow temperament for an Old World Tarantula. They can be very fast and are prone to bolt when startled or when they feel threatened., but in general they are relaxed and laid back, especially with other specimens in a communal set up having been observed by many keepers sharing a roach or cricket as they feed.

This is an opportunistic burrower meaning that they will prefer to burrow down into the substrate, but they will also web up the entrance of their burrow and expand their webbing throughout their enclosure and almost seem semi arboreal like a Green Bottle Blue or Orange Baboon Tarantula. One of the amazing aspects of this species is that not only can they be kept communally, but you can keep them with other M. balfouris from different egg sacs, and there have even been multiple reports of people beginning communals by mixing slings and juveniles. It is probably best when deciding to keep specimens of different sizes together communally to make a new enclosure and move everyone into the new home as opposed to just dropping them into an enclosure that one tarantula has already settled into. And it seems that once a female has matured, if she is not already in a communal set up, she will be less likely to adjust and may not be able to co habitate peacefully with other specimens. And it is definitely not recommended to try and house a mature female and mature male together if they were not raised together in a communal set up. I have one Blue baboon that i got a few years ago that i keep by itself in an enclosure and I rarely see it out and about. But i also have a communal with spiderlings and in that set up I almost always see 2 or 3 of them roaming around, occasionally i will find all five out in plain view.

I keep my spiderlings in my usual spiderling acrylic enclosure that is taller than it is wide. I fill it ½-¾ with substrate like coco fiber, peat moss, or a mix of the two, and provide a water dish, a hide, and a few little branches or plants for the spider to use as anchor points for its webbing. I keep the water dish full and once every week or two will overflow the water dish so a corner of the enclosure has damp substrate to help keep things a little more humid than the ambient humidity of the room. If i dint have a water dish or it is too webbed over, i will drip water on its web every couple days but too much to avoid flooding it burrow I keep these slings, like all my slings, in my spiderling nursery that has a temperature a few degrees higher than the average room temperature in my home. I find this helps the spiderling survival rate and growth rate slightly and you can see a video on how I set this up linked in the top right corner. For juveniles I move them into my basic juvenile syle enclosure you have seen in many other videos. Again I make sure it is filled at least halfway with substrate to provide the tarantula with plenty of depth to burrow. Again I supply a hide and some plants to use as wen anchors and give them a water dish I keep full. I don't worry too much about keeping the substrate a little damp at this size as they tend to not mind more arid conditions, but occasionally I will still overflow the water dish. I currently keep my adult in a 3 gallon Zoo Med creature enclosure filled up about halfway with substrate and provide hides, cork bark, plants and water dish. I keep the substrate dry and overflow the water dish a little every month or so. I plan on moving this specimen into a larger enclosure once I am to able to determine its sex. If it is a female, I will most likely keep her in a 5 gallon style enclosure. Though if it is male, I will most likely send him off to breed rather than rehouse him. A good rule of thumb for enclosures for tarantulas any size is to make sure that there is a minimum of 3x the leg span of the T in the surface of the enclosure. As for my communal, I keep my 5 spiderling in a small acrylic enclosure similar in size to my normal juvenile enclosures. This as actually the enclosure they were originally housed in when I purchased this communal from Fear Not Tarantulas at the NARBC in October of 2019. I am moving them into an acrylic enclosure I got from DreamCo plastics once they are large enough and it is time to rehouse them. I don't want to move them too soon though as I have heard if you give them too much space in a communal set up they can go off on their own and establish their own burrows and become territorial. I have no proof of this or any sources to site, I am just airing on the side of caution. As for the final enclosure for my communal as they mature into adults, I have not got that far yet, so you will need to keep watching to get updated on that aspect of their husbandry, though you can check out Toms Big Spiders, Dark Den, or Tarantula Haven for more info and experience on how they keep their communals.

As far as feeding is concerned, I started my first spiderling out with flightless fruit flies and flour beetles twice a week, but once it was over 0.5” i started feeding her 1 or 2 small crickets every 5-7 days. They are voracious eaters and will quickly take down prey, though sometimes they can be a little skittish and will run and hide when I open the enclosure and aren't easy to coax out. On those occasions, I will drop the feeder in the enclosure and check back the next day and remove any uneaten prey still in there. If the tarantula is in premolt it is common for it to go weeks without eating, in which case I am sure to remove uneaten prey immediately and wait about 3-5 days after a molt before attempting to feed again. For Juveniles I feed a small dubia roach (under an inch) or 2 medium crickets every 7-10 days. I remove any uneaten prey or pieces of prey left over within 24 hours. If the tarantula is in premolt, i do not leave any uneaten prey in its enclosure and wait 7-10 days after a molt before attempting to offer it food, giving it plenty of time to harden up. And for adults, I feed my Blue Baboon 1 Dubia roach a little over an inch or 4-5 adult crickets every 10-14 days. I tend to feed a little more after a molt and less the closer the tarantula is to premolt.

This is obviously a stunning and unique tarantula and a great addition to any collection for keepers of intermediate or higher levels of experience. Though this is a more docile species, I would not recommend it to new keepers as its speed and venom can be a little intimidating for beginners. But if you are ready to transitions for New World to OW species, this would make a great species to begin with. Keeping them communally may take a little more experience dealing with OW species before taking that on in your collection. The care and husbandry would essentially be the same, but the challenging aspect would be rehousing the communal. Trying to transfer multiple M. balfouris from enclosure in to another can be very stressful and difficult and can lead to one or two of them bolting out or even giving a threat pose. So having plenty of experience rehousing OW tarantulas would be ideal before attempting to take on a communal.