By Emma-Louise Nicholls, on 2 April 2013
I love it when Specimen of the Week lands on an interesting date. The 1st April is known for a few things, most obviously it is April Fool’s Day. Perhaps less obviously, it is the 31st anniversary of the birth of one of our staff members. An internet search of the date introduced me to the world of housing benefit changes, the new tax year, an Easter egg hunt (which I subsequently signed up for) and the fact that if you want cheaper tickets to some music festival or other, you should have booked before today’s date. What it doesn’t mention however, not even by page 4 or 5, is an article on howler monkeys that was written with the help of information gleaned from several reference resources including an online encyclopedia of animals that to write the aforementioned article was accessed at 15:23 GMT on the 1st April 2009. That reference to the 1st April is shockingly lacking from more high profile spots in the search engine results. In a small and questionable effort to correct this oversight, this week’s Specimen of the Week is…
**The howler monkey**
1) Our specimen of a howler monkey has not been speciated beyond ‘howler monkey’, and there are reportedly at least ten to choose between. Therefore, I am going to pick one to tell you about, the one that I journeyed across land and sea to track in the wild. That species is the Guatemalan howler monkey. Guess where it is from? (Cough*Guatemala*cough). Although I did go to Guatemala, I actually finally tracked the elusive critters down in Belize, as this species is also found in Eastern Mexico, and all throughout Belize. My journey across Central America involved several overnight bus journeys sat packed between large Latin American men who could snore for the New World, making a local girl laugh until she cried at my attempts to hone the Nicaraguan accent, getting licked in the face by a full grown jaguar, eating the best pineapple I have ever tasted, oh and being the most scared I have ever been for my life, in my life. I have been held up at gun point, held up at knife point, charged by a rhino and dragged to the water’s edge by a crocodile, but never have I been more certain that I was going to die than the day I got to Belize. Buuuuuut that’s another story. This blog is about monkeys and when I finally found the howlers, they were worth every second of blood, sweat and abject terror.
2) Howlers are the largest monkeys throughout the whole of the Americas, and our Guatemalan species is one of the big Daddys within the howler brotherhood. The Guatemalan howler has beautiful, flowing, shampoo-advert-worthy black hair that is silky and dense. The only areas not covered by this covetable asset are the hands, feet, face and the underside of the very impressive, prehensile tail. Male Guatemalan howlers over the age of around four months have one other hairless area, uh hum, a very notably white scrotum which, given that they don’t sit with their legs crossed for much, or indeed any of the time, makes them easy to distinguish from the ladies. The howler’s tail, as with the spider monkeys that we got to know well before, can be used as a fifth limb for both grip and balance.
3) Howlers have a very impressive method of avoiding being renamed the ‘whispering monkey’ or the ‘sit-quietly-or-you’ll-never-hear-it monkey’. They emit a seriously-I-kid-you-not-louder-than-loud rasping bellow that is audible several kilometres away. This ear-splitting cacophony, that can be likened to the start up motor of a Spitfire Mk IX, serves to let other troops know who’s territory it is, attract mates (preferably ones that don’t mind being deafened), and to see off rival troops through intimidation. A sort of auditory ‘my horse is bigger than your horse’. As it were. The specimen that we have at the Grant Museum has the hyoid still in tact. This large pseudo-spherical bone is what allows the howlers to make their incredible signature howl as it acts like an amplifier. It also makes for an impressive skeletal addition to our collections.
4) A troop comprises one or two lucky adult males with a sprinkling of breeding females and whatever biological result this social situation has produced that year. Until they can establish a troop of their own, single gentlemen are known to form bachelor troops which will attempt to commandeer a troop of breeding females for themselves from someone else.
5) Howlers primarily chow down on leaves and fruit though when this gets boring, they will also nab a flower or insect to break up the daily grind. They are primarily active in both the morning and the evening, making them technically crespuscular individuals, however they are also often up for various shenanigans throughout the day as well. All sounds a bit energetic to me, I like my sleep. Although in fairness, many of these troops inhabit forests surrounding a number of Mayan archaeological sites, so with that level of sightseeing to be done everyday, maybe I can understand their eagerness to be out of bed.
Emma-Louise Nicholls is the Museum Assistant at the Grant Museum of Zoology