POISONOUS PRIMATE?!
I am attempting to write this while an insistent orphaned
baby slow loris happily chirps in my ear and nibbles on my nose.
Elvie (LV, named for little voice, not for her stunning vocal
imitations of Judy Garland but rather for her constant nattering!)
has a perpetual battle between her inherent nocturnal nature and
her extremely social tendencies! When we got up, so did she. If
she didn't get the attention she feels she is due, boy do we hear
about it. The Slow Loris name might come from the Dutch word "lores'
which means 'sluggish', which quite amply reflects Elvie as she
moves slowly up your arm towards the golden chalis of a honey
dipped banana. It's amazing how quickly a banana will flee if
you don't creep up on it ever so carefully and then dart out a
hand to grab it in that nano second moment of almost freedom.
Savage chewing finishes off the job since, as we all know, bananas
can be dangerous if they are only wounded.
Having worked extensively with the lorises for the last couple years I am absolutely smitten with them. However, while they have the face of those cute and cuddly gremlins, they have the attitude of the evil, after-midnight flipside. With disproportionately huge and sharp canine teeth (very fang-like) and powerful jaw muscles their bites alone can be absolutely agonising. However, the pain is compounded by factors beyond the simple tissue trauma caused by the mechanical damage from the powerful jaws. The lorises are actually toxic! On the inside of their elbows, sebaceous tissue secretes a toxin (like sweat pores, which is rather fitting since the toxic mixture smells remarkably like sweaty socks). The lorises take it into their mouth and deliver it in the bite. It is not the upper and lower jaw vampire like canine teeth that deliver this toxin. It is the innocuously small teeth in the front of the lower jaw which slope forward and help conduct the saliva into the wound. One time I was working with the large lorises in the research collection and a visiting vet student from Belgium saw me putting on big thick gloves. She asked why I was doing that and I told her about the viciousness of the lorises. She looked at them and said that they couldn't hurt anyone and besides, it wouldn't be any fun to use gloves. I raised an eyebrow and said 'be my guest'. Two hours later, with her hand still painfully throbbing merrily away despite the many ice packs on it, I asked her if she was having fun yet!
The lorises belong to the ancient primate suborder Prosimii ('before apes') and are thus informally referred to as prosimians. This group split from the ape line long long ago and has been evolving separately ever since. It is rather eeiry to think of another primate lineage that theoretically could evolve into a highly intelligent primate that is only distantly related to us. The superfamily Loroidea contains two families, one made up by the lorises (Loridae) and the other by the bush babies (Galagonidae). The Loridae family includes not only the lorises from Asia but also the African agnwantibos (genus Arctocebus) and the Potto (Perodicticus potto). Several features characterise the prosimians, particulaly enhanced night vision brought about through a specialised layer (the tapetum) in the retina of the eye that reflects light. The eye sockets of prosimians are open (unlike other primates) and the brain cases are also much smaller. The Loris' eyes are fixed and cannot move, and like an owl they must swivel their heads around to change their point of view ( ie to look left, right, up, down or behind). Enhanced perception of smell is also characteristic and accompanying this is the extensive use of scent marking through specialised glands.
There are two species of loris described. The pygmy slow loris (Nycticebus pygmaeus) and the slow loris (Nycticebus coucang). The slow loris, however, has several subspecies, some of which may ultimately be proven to be species in their own right. The related slender loris (Loris tardigradus) is, as the name implies, a stretched out version that looks a bit like a long armed anorexic bat or perhaps was the source of inspiration of the swizzle stick look so popular among Hollywood starlets.
The slow lorises range from dark grey to whitish (typified by the Vietnamese populations) but may also be orangy brown (typified by the Malaysian populations). They are are 10 15 inches long and typically weigh around 610 - 1000 grams (most of it located in their bottom!). They inhabit the tropical evergreen rainforest to an elevation of 1.3 kilometers and prefer the insect prey rich forest edges. Their diet is about half fruit with animal prey making up the majority of the remainder. The Slow Loris becomes sexually mature at 17-20 months and can live up to twenty years. They usually pop one or two live young every year or so, having gestated it for around 191 days. If you were to calculate this in an 'ideal' environment, that would make approximately 18 kids per female lifespan. (Surely a massive investment in schooling and tertiary fees!)
Unlike most primates, the lorises do not leap through trees. Rather they carefully and methodically move their feet in an almost chameleon-like manner, an impression greatly enhanced by thumbs that are more opposing than other primates. Specialised blood vessels allow them to grip on for hours. (This seems especially true when I'm trying to get some work done and Elvie will not let go of my hand and let me type!) When disturbed, (like trying to press return on my keyboard) lorises make a very unique low buzzing sound, much as if they were trying to play the digeridoo but without a didge or using their lips! True talent. In addition to this, when Lorises feel that battle stations is necessary, they fold their arms into a diamond around their head. While this looks incredible cute and useless as a defence mechanism, it allows for them to quickly take the toxin from their fore arms into their mouth in preparation for biting. This is reminiscent of karate moves at the last draw corral. Ah, I see you know the grasshopper, but do you know the Slow Loris?!
The mystery of this toxin is currently being unlocked as we have isolated the toxin and are in the process of characterising it. It is shaping up to be a fascinating piece of adaptive evolution and takes steps to explaining such things as why it is an effective survival mechanism for the mother to comb the baby over with the toxin which may protect it in her absence. Surprisingly it appears that the toxin is highly similar to the protein in cat dander that is responsible for cat allergies! This not only gives some indications as to the potential mechanism of action of the toxin but also raises the question as to whether the cat allergy is actually deliberate on the part of the cat and is actually a toxic defense! As Elvie has gotten older and started to secrete the toxin herself, Alexia has actually started to sneeze and itch around her. A most unfortunate development for such a cute little part of our family (and Elvie as well!). In keeping with their being toxic, the lorises have a special fondness for eating noxious fruits and insects. While the alkaloidal chemicals from the fruits and insects are not incorporated into the toxins (unlike the poison arrow frogs for example) there is some emerging evidence that they might serve a use in the scent marking through urine. Other favorite food includes geckos. Elvie likes nothing better than tear the head off of a still moving gecko, happily chew that and then start on the rest of the body. The twitching tail is saved for last and is a special piece of fascination for her.
LV was very helpful when I was trying to type. If she was a good
girl, she would get rewarded with a freshly caught live gecko.
She would bite the tail off first, then work her way up to the
eat, saving the squiggling tail for last as it seemed to hold
a particular fascination for her.
Sadly Lorises are often poached from the wild to be kept as pets. In the wild they are solitary animals and this provides challenges for their care in captivity, especially in refuge centres caring for abandoned pet lorises or orphaned babies. Wandering through any of the big markets in Indonesia, it is not uncommon to find them up for sale with their canine teeth removed. This reduces the effectiveness of the slow loris's bite. It also removes the loris's ability to feed on a balanced diet that includes those fascinating geckos. However, the pet trade is not the major threat to their survival in the wild. As is depressingly typical, the real threat comes from habitat destruction and killing for use in Asian medicines.
Elvie's hands are a constant source of fascination to us. It is eerie to look at them, every time we see them it strikes a deep chord. Something within us recognises that even though the lorises split off from the main primate tree long ago, we are still related. In fact, possessing the academic knowledge about the deep split between the two lineages yet still seeing such human-like hands really brings home the fact that we are part of the same clade. Elvie has some behaviours that are range the full gamut from extremely cute through to absolutely adorable! One morphological adaptation is our favorite, we have named it the 'butt pillow'. Imagine a loris sitting like a prarie dog (ie legs straight out in front of it), have it stick the bottom out a bit more and then use it like a pillow! As lorises are rather pungent creatures, it is quite logical that when it wants to seek out somewhere secure (ie that reminds it of mum (the biological one, not Alexia!) it curls up in the laundry, particularly if it is filled with sweaty clothes from triathalon training! As for its view of dad (me), I am the great provider.. it is my job to go out and catch it the fresh geckos that it just loves! All in all, what more could you ask for out of a child! Thus, our family consists of a child with a butt-pillow, sweaty laundry = mum and it is all rounded out by the gecko providing father. The Adams family have nothing on us!
One of the best times we've had while doing mammal research has been playing with the baby Asian palm civets (Paradoxurus hermaphroditus). These little guys were absolutely adorable. Palm civets are Asian nocturnal predators, best described as a cross between a racoon and a cat.
