THE ANIMAL FILES

West Indian manatee

Trichechus manatus

A manatee explores with hairs far beyond the edges of its face.

The West Indian manatee feeds largely on aquatic vegetation in fresh and salt water. Sensitive hairs across its body and face help it investigate the surroundings, and mobile lips grasp food. Its feeding apparatus combines touch, manipulation and teeth that are repeatedly replaced as they wear.[1]

Follow the evidence ↓
West Indian manatee
Image: Galen Rathbun · Commons · Public domain
Main foods
Aquatic vegetation, including seagrasses[1]
Touch sensors
Vibrissae on face and body[1]
Teeth
Molars are replaced repeatedly during life[1]

Grasping with the lips

The lips are highly mobile and prehensile: they can grasp vegetation and objects. Dense facial vibrissae supply touch information during this action, while bristle-like hairs on the oral region also investigate food and objects. Finding and manipulating a plant is therefore not solely a matter of seeing it and closing the jaws.[1]

Touch through murky water

Body-wide vibrissae contain sensitive nerve endings. Research shows texture discrimination and detection of water movement. These functions can help in turbid waterways where vision is restricted. The comparison with a fish’s lateral line concerns detecting hydrodynamic signals, not possession of the same anatomical structure.[1]

A plant diet that wears teeth

Seagrass is important in coastal feeding areas, and many other aquatic plants are eaten. Abrasive food wears molars, which are replaced repeatedly through life—the “marching molars” description refers to this replacement system. An enlarged hindgut supports digestion of plant material. Occasional animal food is also reported despite this plant-focused diet.[1]

A COMMON MIX-UP

Are its whiskers confined to the muzzle?

No. They occur across the body, with especially dense concentrations on the face.[1]

TRY A LITTLE REASONING

Why is repeated molar replacement useful to an animal that grinds abrasive plants?

Reveal the explanation

Worn grinding surfaces can be replaced as plant feeding continues, instead of relying on one permanent set for life.[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 — Trichechus manatus (adapted and translated; exact revision)
  2. NCBI Taxonomy — Trichechus manatus (identity and game lineage)

Last fact check:

One discovery leads to another

African bush elephantGrass, branches and water leave their marks on elephant society.Loxodonta africana ↗Rock hyraxSoft foot pads put a small plant-eater at home on rock.Procavia capensis ↗AardvarkA sticky tongue meets a muscular stomach.Orycteropus afer ↗