Contributed reagents/materials/analysis tools: LLT-D CDM TJD. The species is territorial, with groups marking their ranges with latrines, gland secretions, and vocalizations. Mustelidae (weasels, otters, badgers and skunks) is one of the most ecologically diverse families in the order Carnivora and provides interesting opportunities to explore the morphological and biomechanical diversity of feeding [6]. A wavering scream may be used in bluff charges against intruders, while a low growl is used for aggressive warning. The survival of the giant otter populations in the Guianas is essential to the survival of this endangered species in South America. [11] Both species also show strong pair bonding and paternal engagement in rearing cubs.

2004. Similar to giant river otters, North American river otters possessed relatively long mandibles with a relatively low MBI, which should place the resulting force (any bite location such as canines, carnassials, back molars) farther from the TMJ, again providing the advantage of high velocity jaws to catch fast prey in open water. Other water habitats include freshwater springs and permanent freshwater lakes. Subspecies acronyms are (ken, E. l. kenyoni; lut, E. l. lutris; ner, E. l. nereis). [26] Unique markings of white or cream fur color the throat and under the chin, allow individuals to be identified from birth. They are extremely easy to hunt, being active through the day and highly inquisitive. Yes https://doi.org/10.1371/journal.pone.0143236.s004. They also possessed the greatest coronoid length, an insertion of the temporalis muscle, which increases surface area for muscle attachment and correlates with a larger moment arm of temporalis. A greater moment arm of the masseter also generates more control over mastication [61]. An IUCN study in 2006 suggested 1,000 to 5,000 otters remain.

Small chisel-like teeth at the front of the jaws can be used to groom the fur. [40] Population densities varied with a high of 1.2/km2 (3.1/sq mi) reported in Suriname and with a low of 0.154/km2 (0.40/sq mi) found in Guyana.

A similar situation (shorter and wider skulls) has been reported for phyllostomid bats in which direct bite force at the jaw tips was measured [62].

[42][43] Within groups, the animals are extremely peaceful and cooperative. Northern and Russian sea otters possessed relatively larger faces and moment arms of the masseter, and wider zygomatic fossae. In the wild, it has been suggested, although not systematically confirmed, that tourists cause similar stresses: disrupted lactation and denning, reduced hunting, and habitat abandonment are all risks.

Discriminant analysis correctly classified over 99% of otters to their feeding specialization using both form and shape data and over 97% for form and shape in the validation procedure (S1 and S2 Tables).

The vector for OSA½ proceeds approximately three-fold more than shown. This suggests increased force at the anterior jaws near the canines. Ellipses depict standard errors for regression scores. [71] Duplaix relates the story of an Arawak Indian who took two pups from their parents. High velocity jaws are an important adaptation for mouth-oriented species that prey upon fast moving prey, such as fish. [71] Specific threats from human industry include unsustainable mahogany logging in parts of the giant otter range,[68] and concentrations of mercury in its diet of fish, a byproduct of gold mining.

Northern sea otters displayed the greatest MAmasseter, followed by southern and Russian sea otters. Sea otters possess large occlusal surface areas (OSA) of the postcanine teeth. Therefore, the mechanical advantage of the masseter (MAmasseter) was measured by dividing the MAM by the distance from the posterior-most condyle process edge to the posterior of the lower carnassial (OLC) as follows: MAT was measured as the distance between the dorsal surface of the mandibular condyle to the apical tip of the coronoid process (Fig 1).