Frequently Asked Questions

The River Otter Alliance provides this information in good faith and does not assume responsibility or liability for any action taken or not taken in reliance thereon.
By far, the most frequently asked question relates to otters in the pond. Otters that predate on stocked fish, interact with or threaten pets, frequent areas also used by children, etc. Writers have come from different parts of the U.S. - and even from the U.K.

Here are some answers.

"North Carolina started a restoration program for otters in 1992.  However, because river otters are abundant in eastern NC today, they can be harvested during the open trapping season. In western NC it has been illegal to trap otters since 1935. Unfortunately, NC does not have a Wildlife Damage Control Agent for Person County.  So, he needs to report his situation to the state Wildlife Biologist for his district. NC Wildlife Law Enforcement Officers, NCWRC Wildlife Biologists, and WDCAs can issue Wildlife Depredation Permits to citizens at no charge. I think his first action should be to seek advice from the state authorities trained to handle this situation. Perhaps he could seek professional assistance to trap the otter and relocate it to a western area in his state."

"Otters sometimes wreak havoc for those trying to rear fish. I would suggest that the pond owner put a fence around the pond that also goes down into the ground. Problem solved. No need to trap the otter(s) to protect the fish then. If you trap an otter or two from the pond, and if the population density is high, then others from the surrounding area will eventually migrate and fill the previous void. This necessitates more trapping. Fencing is a long term solution. "

"Another idea is to provide more cover for the fish such as aquatic vegetation or artificial cover (old Christmas trees). This gives the fish more cover and makes it harder for the otter to capture their prey."

"Otters are very resourceful and opportunistic. They can survive wherever there is a fresh-water stream or river flowing through a riparian habitat, as long as there is a food source. They feed primarily on fish - mainly slow-moving fish, if they're available - and crayfish, but they've been known to take small birds and mammals. They den up to 500 yards from a river or stream. They do not excavate their own dens; they appropriate other animals' dens, or use natural (or man-made) formations. (They love boat docks - both to den underneath them and to defecate on top of them!) They prefer to introduce their young to slower currents at first. In fact, otters do not take readily to water. They need to be 'strongly encouraged' by mom to enter the water the first time. Otters have long home ranges. It largely depends on the distribution of their food source and competition from other otters. Males have longer home ranges than females - and will overlap two or more females' home ranges. A researcher in Colorado reported one male's home range was 38 linear miles. Another in Idaho had a male whose home range was ~100 miles."

"River otters, like most other wildlife, don't look for trouble, but will vigorously defend themselves, their food, and their young. That said, river otters, like most animals, are more afraid of you than you are of them. Otters have been known to contract (short list) the viral diseases: canine distemper, canine parvovirus, rabies (animal foaming at the mouth), infectious canine hepatitis, feline rhiotracheitis, herpesvirus, the bacterial diseases: pneumonia, clostridial infection, enteritis, tuberculosis, purulent pleuritis, purulent peritonitis, brucellosis, leptosporosis, pasturellosis, and salmonellosis, the fungal diseases: dermatomycosis, coccidiodomycosis, and adiaspiromycosis, and the protozoans: giardiasis, and coccidiosis. At last count, river otters as a species are known to have about 6 species of tapeworms, 13 different flukes, 8 types of spiny headed worms, and 29 different kinds of roundworms. In most cases the parasite load is light. Humans, and our dogs and cats, are known to have a great deal more parasites and diseases than otters. The vast majority can not be transmitted but some can. The main means of transmission of diseases from other animals to humans is by biting, ingestion of parasite bearing feces, lesions in the skin, drinking contaminated water (or swimming and accidentally swallowing), and mucous membrane contact. With this caveat or caution, if you are supervising your children, these otters don't pose a real threat to your children's health. Encourage your children to observe but not to touch wildlife. I would not recommend leaving your pets unattended. You may want to redo your sea wall or construct a fence if the "problem" persists. If all else fails and you've addressed those issues then contact your local wildlife officer. Sometimes otters will frequent a place while the fishing is good and then move on when it is not so good. In the meantime grab a camera and get some photos."

 

Can you recommend books, current research or a contact for a 3rd grader who is working on a report on  the "European Otter" and is requesting information for her school  project?

 

For Eurasian otters (Lutra lutra) I would recommend C.J. Harris, 1968, Otters, a Study of the Recent Lutrinae; Paul Chanin, 1985, The Natural History of Otters, Hans Kruuk, 1995, Wild otters: Predation and Populations; Gavin Maxwell, 1969, Ring of Bright Water. For articles look up Mason, Chris and Sheila MacDonald, or Claus Reuther. Also do a Google search on "European otter, Eurasian otter, or Lutra lutra" - and I.O.S.F. (www.otter.org), of course.

 

What characteristics place otters into the Genus Lutra rather than in another genus of the Mustelids family?

"There are several factors that govern the placement of species in a particular taxonomic realm. And while it may seem, that when those factors are considered, it is merely matter of fact where a species should be placed, it often becomes controversial. The North American River Otter is such a species. In fact, in the last decade, the N.A. River Otter was removed from the genus Lutra and placed in the genus Lontra to conform to other New World Otters. Lutra is now reserved for Old World otters. But even to this day, there are those who still refer to the N.A. River Otter as Lutra canadensis.

One of the main factors in taxonomic placement of a species is dentition. Variations in jaw and tooth structure usually separate species and often genus. Another is reproduction. As a rule, animals of different species cannot produce fertile offspring. Of course, now that DNA testing is commonplace, genetic variations in species can be detected so they may be placed in their correct genus.

Click on this link for a reference for the classification of species from the fossil record.

References about classification of otters in particular may be found at lioncrusher.com and zoo.org  among many others."

"Contact The International Commission on Zoological Nomenclature, based at the Natural History Museum in London, UK.  Their email address is iczn@nhm.ac.uk."

 

We've been watching an otter in a pond in north central Arkansas these last couple of snowy, cold days.  Is it the same species as the river otter?  How would an otter--a single animal--get to a pond that is several miles from the nearest river? "While otters are semi-aquatic, they move pretty well on land also. This could be a male that reached maturity and was forced to find its own way, or a case where the food resource in its previous habitat became scarce. Otters are very resourceful, and will find their way to the nearest food resource by whatever means necessary."

How much does an otter eat daily?  I read it eats 60% crayfish in the summer and 60% fish in the winter when crayfish are hibernating. Depending on the reference, an otter eats between 1.5 and 3.2 pounds of fish per day; the consensus average is about 2 pounds. And yes, otters will eat crayfish and other crustaceans when they're abundant. Additional information about otter diet can be found in several articles in the River Otter Journal. Check out our index of articles by subject.