Above: A North American river otter in her den with young pups.
(North American river otter, Daniel J. Cox, www.arkive.org) |
Above: A mother European river otter with her pups.
(European river otter, Dave Kilbey, www.arkive.org) |
Lontra Canadensis
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Lutra lutra |
A Unique Reproductive Technique
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Sexual Maturity
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North American river otters have the ability to undergo delayed implantation, in which they retain a fertilized egg for up to 8 months before allowing it to implant (Reed-Smith, 2001).
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Female European River Otters reach maturity between 18 and 24 months of age. In a study conducted by Hauer et al., a female European River Otters as young as 2 years of age was discovered to have placental scarring, indicating that at least one litter had been conceived.
(Hauer et al., 2002) |
Litter Size
In a study conducted in Northern California, citizens were used to collect data on North American river otter populations and group sizes ( Black, 2009). In this study the average litter size was determined to be 2.2 pups, with the largest litter sizes being documented in spring (Black, 2009).
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Litter Size
The average litter of the European river otter contains 1-2.5 cubs (Ruiz-Olmo et al., 2011). However, in another population census conducted by Hauer et al. litter sizes ranged from 1 to 5 cubs, with the largest litters being born in the winter.
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Uterine Structure
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Birthing Season
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The North American River Otter has a bicornuate uterus; a uterus with a distinctly Y-shaped structure (Hamilton and Eadie, 1962).
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Lutra lutra are more unique in their reproduction than other otter species due to their extensive range in various climates. Seasonality of reproduction occurs with decreased food availability, in areas like Norway and Sweden. However, in temperate climates breeding occurs throughout the year, with Lutra lutra being the only otter to demonstrate this.
(Chadwick and Sherrard-Smith, 2010) |
Sexual Dimorphism
Parental Roles
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Parental Roles
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Care of pups falls almost solely on the dam, with additional females helping out on occasion. Male otters very rarely help with pups, as females won't often let them near their young until after 3 months of age.
(Hamilton and Eadie, 1962) |
Mother otters take care of their young from 10-15 months of age, at which time the young are weaned. In accordance with this, lactation can occur throughout all times of the year.
(Chadwick and Sherrard-Smith, 2010) |
Gestation Period
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Gestation Period
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Reports have been historically varied on the gestation period of the North American River Otter. The most frequent reports place the gestation period between 50 and 63 days.
(Reed-Smith, 2001) |
The gestation period of the European river otter is a range from 61-63 days, though research on this is not extensive (Chadwick and Sherrard-Smith, 2010). The overall gestation is likely quite similar to that of its North American cousin.
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References
1. Arkive. 2015. Common otter (Lutra lutra). Available: http://www.arkive.org/common-otter/lutra-lutra. Accessed March 2, 2015.
2. Arkive. 2015. North American otter (Lontra canadensis). Available: http://www.arkive.org/north-american-otter/lontra-canadensis. Accessed March 2, 2015.
3. Black, J.M. 2009. River otter monitoring by citizen science volunteers in northern California: social groups and litter size. Northwestern. Nat. 90(2): 130-135.
4. Chadwick, E., and E. Sherrard-Smith. 2010. Pregnancy among otters (Lutra lutra) found dead in England and Wales: foetal development and lack of seasonality. IUCN Otter Spec. Group Bull. 27(1): 33-41.
5. Hamilton, W. J., W. R. Eadie. 1962. Reproduction in the otter, lutra canadensis. J. Mammal. 45(2): 242-252
6. Hauer, S., H. Ansorge, and O. Zinke. 2002. Reproductive performance of otters Lutra lutra (Linnaeus, 1758) in Eastern Germany: low reproduction in a long-term strategy. Biol. J. Linn. Soc. 77: 329-340.
7. Jackson, H.H.T. 1961. Mammals of Wisconsin. pg. 383
8. Reed-Smith, J. 2001. North American River Otter. 2nd ed.
9. Ruiz-Olmo, J., A. Batet, and F. Manas. 2011. Factors affecting otter (Lutra lutra) abundance and breeding success in freshwater habitats of the northeastern Iberian Peninsula. Eur. J. Wildl. Res. 57: 827-842.
2. Arkive. 2015. North American otter (Lontra canadensis). Available: http://www.arkive.org/north-american-otter/lontra-canadensis. Accessed March 2, 2015.
3. Black, J.M. 2009. River otter monitoring by citizen science volunteers in northern California: social groups and litter size. Northwestern. Nat. 90(2): 130-135.
4. Chadwick, E., and E. Sherrard-Smith. 2010. Pregnancy among otters (Lutra lutra) found dead in England and Wales: foetal development and lack of seasonality. IUCN Otter Spec. Group Bull. 27(1): 33-41.
5. Hamilton, W. J., W. R. Eadie. 1962. Reproduction in the otter, lutra canadensis. J. Mammal. 45(2): 242-252
6. Hauer, S., H. Ansorge, and O. Zinke. 2002. Reproductive performance of otters Lutra lutra (Linnaeus, 1758) in Eastern Germany: low reproduction in a long-term strategy. Biol. J. Linn. Soc. 77: 329-340.
7. Jackson, H.H.T. 1961. Mammals of Wisconsin. pg. 383
8. Reed-Smith, J. 2001. North American River Otter. 2nd ed.
9. Ruiz-Olmo, J., A. Batet, and F. Manas. 2011. Factors affecting otter (Lutra lutra) abundance and breeding success in freshwater habitats of the northeastern Iberian Peninsula. Eur. J. Wildl. Res. 57: 827-842.
Banner: North American river otter, Thomas D. Mangelsen, www.arkive.org; North American river otter, Tom and Pat Leeson, www.arkive.org; North American river otter, John Cancalosi, www.arkive.org; Common Otter, Laurie Campbell, www.arkive.org; Common otter, Henry Ausloos, www.arkive.org; Common otter, Laurie Campbell, www.arkive.org; Common Otter, Jorg and Petra Wegner, www.arkive.org; Common otter, Wild Wonders of Europe, Campbell, www.arkive.org; North American river otter, Gordon and Cathy Illg, www.arkive.org