''Lutra'' is a
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
otter
Otters are carnivorous mammals in the subfamily Lutrinae. The 13 extant otter species are all semiaquatic, aquatic, or marine. Lutrinae is a branch of the Mustelidae family, which includes weasels, badgers, mink, and wolverines, among ...
s, one of seven in the subfamily Lutrinae.
Taxonomy and evolution
The genus includes these species:
Extant species
Extinct species
*†''
Lutra affinis''
*†''
Lutra bressana ''
*†''
Lutra bravardi''
*†''
Lutra castiglionis''
*†''
Lutra euxena''
*†''
Lutra fatimazohrae''
*†''
Lutra franconica''
*†''
Lutra hearsti''
*†''
Lutra palaeindica''
*†''
Lutra simplicidens''
*†''
Lutra trinacriae''
The genus most likely evolved in Asia during the late
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58[amphibians
Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...](_blank)
(mainly frogs and pond turtles), bird predation (mainly anserine species), small
rodents
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are n ...
, and
invertebrates
Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordate subphylum ...
such as water beetles, snails, and crayfish. They have also feed on plants, specifically grasses. With this large diversity of prey and resources for their diets, otters are considered "opportunistic eaters".
Behavior
Some otters live in
solitude
Solitude, also known as social withdrawal, is a state of seclusion or isolation, meaning lack of socialisation. Effects can be either positive or negative, depending on the situation. Short-term solitude is often valued as a time when one may wo ...
, while others live in groups.
''Lutra'' species are known to exhibit strong territorial behavior. Family group territories are distinct from those of solitary male ''Lutra''. In a family group, adult males can be seen patrolling and defending their territories while females will raise their cubs in a secure area within the males' territories. Additionally, a family group choose areas that are rich in resources to support their cubs during the first year. Solitary males, however, choose their territory for reproductive purposes and ensure they have access to breeding females. These territories are marked with
spraints as a means to claim ownership and deter rivals. As a result, there are overlapping boundary zones that cause many conflicts between males and is resolved through threatening signals and avoidance.
References
{{Authority control
Otters
Carnivoran genera
Fauna of the Palearctic realm
Taxa named by Mathurin Jacques Brisson