THE ANIMAL FILES

Yucatán black howler

Alouatta pigra

A leaf eater can announce its presence without travelling to every rival.

The Yucatán black howler is a Central American tree-dwelling monkey. Adults have long black hair and a gripping tail, while infants begin with brown fur. Leaves and fruit are important foods.[1]

Follow the evidence ↓
Yucatán black howler
Image: Charles J. Sharp · Commons · CC BY-SA 4.0
Activity
By day, mainly in trees[1]
Teeth
High shearing crests on molars[1]
Voice
An enlarged hyoid helps amplify male calls[1]

Teeth meet a leafy diet

High ridges on the molars help shear leaves. Fruit and some flowers also occur in the diet, and the balance can vary seasonally. A leaf-oriented anatomy does not mean only one plant part is ever eaten.[1]

Sound travels while the animal stays

The male’s enlarged hyoid bone lies near the vocal apparatus and amplifies calls. Howling is common around dawn and dusk. Other monkeys can receive information about its presence without a close encounter.[1]

Rest is a large part of the day

Much of the day is spent resting, interrupted by feeding, moving and social activity. The monkeys live in groups rather than treating each tree as an isolated individual territory.[1]

A COMMON MIX-UP

Does the Belizean nickname “baboon” make it an African baboon?

No. It is a New World howler monkey. A local common name is not a statement of close relationship to African baboons.[1]

TRY A LITTLE REASONING

How can calling reduce the need for a close encounter?

Reveal the explanation

A loud signal conveys presence across space, allowing other animals to detect a caller without approaching its exact branch.[1]

Sources & editorial notes

Adapted and translated from the cited Wikipedia revisions, with source-linked reasoning. Image credit and licence are listed separately above.

Adapted and translated from Wikipedia contributors; exact revisions are linked below. CC BY-SA 4.0

  1. Wikipedia contributors — Yucatán black howler (fixed revision; adapted and translated)
  2. NCBI Taxonomy — Alouatta pigra (identity and classification)

Last fact check:

One discovery leads to another

Golden lion tamarinLong fingers find meals where eyes cannot look.Leontopithecus rosalia ↗Wedge-capped capuchinA dark wedge on the head, and a forest life shared with helpers.Cebus olivaceus ↗Japanese macaqueA troop can inherit habits as well as share a home range.Macaca fuscata ↗