Fast Fact Attack: Endangered Species No. 77 – The Northern Brown Howler


Brown howler monkey (Alouatta guariba)

Photographer – Peter Schoen

“We are living on the planet as if we have another one to go to”
Terry Swearingen

If you have ever been lucky enough to have heard a howler monkey calling in the wild, you will know how it got its name.  Arguably one of the loudest animals on the planet, they can be heard up to three miles away through the dense jungle.  Alexander von Humboldt said about howler monkeys, “their eyes, voice, and gait are indicative of melancholy”.  The howlers in this clip may not be of the sub-species guariba guariba, but the sound is typical of the species in general.  And, believe me, this is not something you need to take you by surprise in the dark.

The International Union for Conservation of Nature (IUCN) lists most of these sedentary, arboreal howler monkeys (fifteen species) as threatened, due to human activities such as ceaseless hunting for bush meat, and habitat loss and degradation.  But, for the most part, the howlers are still fairly plentiful, with the exception of the Mexican howler (Alouatta palliata mexicana – a sub-species of the mantled howler) and today’s highlighted species, the northern brown howler (Alouatta guariba guariba).  They have both suffered to the point of being driven to near extinction.

Howler monkeysHowler monkeys are a large and inexpensive source of protein.  One monkey could easily feed a family of four.  And, they are slow and docile, which makes them easy prey.  Then, there are the usual illegal logging activities and other forms of human encroachment that we see everywhere across the globe.  The locations change, but the threats remain the same.

Howlers are not only large themselves, but they are also among the largest of the New World monkeys.  They range in bodily height from two to three feet.  Added to that, they have extremely long, prehensile tails which can measure anything from three feet to an astounding three times the size of the monkey itself.  This tail is invaluable to the New World monkeys.  They use it to travel through the branches and can wrap it round and swing freely to pluck leaves and fruit with their hands.

Another helpful augmentation of the howlers is their incredibly keen sense of smell. They have short stumpy, round noses which Howler monkey (Alouatta guariba) in Santa Maria de Jetiba, Brazil.can sniff out nourishment (the nostrils have sensory hairs inside) at over two to three miles.  Possibly no coincidence that they can be heard that far away as well.

A further adaptation is the molars, specially designed to shear through tougher leaves.

But, it doesn’t end there.  These marvellous monkeys are also blessed with trichromatic colour vision, which is thought to have developed in the species to allow selection of the very best leaves available.

One last staggering attribute is, of course, that voice.  A combination of large throat with specialised vocal chords and larynx produces a whole range of growls, barks, howls and roars.  This ability is unique to the howler species.

Howler monkeys are slow-moving folivores.  They spend most of the daylight hours relaxing in the trees.  The rest of their time is shared between eating, travelling and grooming. They move quadrupedally along the tops of branches, using their hands and their long, strong tails.  They live in groups of four or five.  Occasionally there are more. One dominant male usually rules the troop.

Baby howler monkey at the Sloth Sanctuary, Costa Rica by Jonathan LeyHowler monkeys do not have a specific breeding season, but females are only able to produce offspring every twenty-two months.  One infant will be born as a result of the liaison, after a gestation period of six months.  Most infants are weaned at one year, and reach maturity at five years (male) and approximately three and a half years (female).

The species, brown howler monkey (Alouatta guariba), lives in forests in south-eastern Brazil and far north-eastern Argentina.  There are two sub-species; today’s featured northern brown howler (Alouatta guariba guariba), listed as ‘critically endangered’, and the southern brown howler (Alouatta guariba clamitans) listed as ‘of least concern’.

Habitat
Sub-montane, montane and lowland forests.
Where
Brazil:  The Northern brown howler is confined to a small area north of the  Rio Jequitinhonha.  The Jequitinhonha flows through the Brazilian state of Minas Gerais.
What they eat
Mature leaves, though younger leaves are preferred.  Mature fruit is also an important part of the diet.  And, they will also eat, buds, flowers, and nuts.
Threats
Hunting and  deforestation, hunting being the larger threat as they are ale to  survive in small fragments of forest if they are left alone by hunters.  They are both susceptible to, and carriers of, disease.
Status: Critically Endangered
The Northern brown howler (Alouatta guariba guariba), is listed on the  IUCN Red List of Threatened Species  as Critically Endangered.  It has been on the critical list since 1996.  It is also protected by  Cites Appendix 11.  Little over two hundred of the species still survive in the wild.  I have been unable to find any record of Northern howler monkeys being kept in zoos, either in captive breeding programs or as an attraction.

Related Articles
Howler monkey at risk of extinction because of stress

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Fast Fact Attack: Endangered Species No. 59 – The Sumatran Elephant


Sumatran elephants in the jungle

Image: Green Global Travel

Description
Why is somewhere so richly bio-diverse as Indonesia losing its wildlife at such an alarming rate?  Why are the Sumatran tiger, the Javan and Sumatran rhino, and the Sumatran orangutan, all endangered?  And, why was the Sumatran elephant moved from endangered to critically endangered, on the IUCN Red List, in 2012?  Collectively, difficult questions to find the answers to, perhaps!

Well, no… not really.  There is no mystery attached at all.  It is not poaching, disease or the illegal pet trade, but  palm oil  which they have fallen victim to, and which has now become the principal threat to the survival of the Sumatran elephant.  For goodness sakes people, stop buying palm oil-based products now.  Palm oil is ‘liquid ivory'”  [1]  to the unscrupulous.  Do not feed the greed. This elephant is rapidly losing its habitat, and dying off at a terrifying rate because of it.

For a full, up to date report on the destruction caused by palm oil plantations,  click here.   Trust me – it will both shock and disgust you.

The Sumatran elephant is a recognised subspecies of the Asian elephant, and native to the Indonesia island of Sumatra.  These magnificent creatures can grow to between seven and ten feet at the shoulder.  They weigh in at an incredible six and a half to eleven thousand pounds, and surprisingly can run up to twenty-seven miles per hour.  They have leathery grey skin and smaller ears than African elephants. They also have an extra pair of ribs.  Females tend to be smaller than males and often do not have tusks.  Those that do, have them tucked safely away under the upper lip. That surely has to be a plus for the Sumatran elephant.

Elephants wallow a lot.  This endearing habit is very important.  It protects their skin from harmful insect bites and cools them down at the same time.  They also migrate, following strict routes.  The herd is led by the eldest elephant who is expected to remember its herd’s route from the previous trek.  Migration takes place between the wet and dry seasons, when they can walk up to seven kilometres in a single night.  Should they need to cross rivers, elephants are able to submerge themselves underwater and use their trunks as snorkels.  On their travels, they communicate with each other using sounds produced by soft vibrations of the trunk.  These sounds can be heard by other elephants up to five kilometres away.

There is no particular breeding season for elephants, but the rainy season seems quite popular.  Females are ready to breed by the time they are ten years old.  There is a gestation period of twenty-two months, after which a single calf will be born.  Calves weigh about one hundred kilos and are normally taken care of by other females in the herd, as well as the mother.  Infants stay with their mothers until they are five years old.

Who is responsible for the decline of the Sumatran elephant?
(An excerpt from the Rainforest Action Network factsheet on palm oil plantations)

“North American food and agribusiness companies purchase from, operate, and own many palm oil plantations in South-east Asia, making our corporations a powerful force in the palm oil market.
The largest privately owned company in the U.S., Cargill dominates the American palm oil market. They own five palm oil plantations in Indonesia and PNG and are the largest importer of palm oil into the U.S., sourcing from at least 26 producers and buying roughly 11 percent of Indonesia’s total oil palm output. A large and growing number of investigations have shown that Cargill’s palm oil is directly destroying forests, eliminating biodiversity and harming forest peoples.”

Companies such as Nestlé and Unilever are also heavily involved.

Read more:  Problem with Palm Oil Factsheet | Rainforest Action Network

Habitat
Lowland forests.
Where
Sumatra – Indonesia.
What they eat
Green vegetation and fruit.  The Sumatran elephant  and can munch its way through two hundred kilos of food a day.
Threats
Mainly oil palm plantations, followed closely by timber plantations for pulp and paper production, and land clearance for agricultural use. Elephants have also been shot and poisoned by local farmers.  Natural predators are few.
Status: Critically Endangered
The Sumatran elephant  (Elephas maximus sumatranus)  is listed on the  IUCN List of Threatened Species  as Critically Endangered.  There are an estimated two thousand of the species left in the wild.  The World Wide Fund For Nature predicts that within 30 years this South-east Asian elephant could be extinct.  The Sumatran elephant is protected under Indonesian law, though this has not been enforced efficiently in the past.  This year,  WWF  have been working with partners in Sumatra to  “prevent destruction of forest habitat and secure well-managed protected areas and wider forest landscapes connected by corridors”.  The government of Indonesia has now passed a new law setting maximum boundaries land use.  This has upset the plantation owners and their investors.  “For example, the production target of 40 million tons of palm oil by 2020 is in jeopardy”.  [1]

For a full, up to date report on the destruction caused by palm oil plantations,  click here. (just in case you missed it at the beginning)

“We are living on the planet as if we have another one to go to”
Terry Swearingen