By Sarah Shimek, Education Coordinator
5. Bald Eagles
While bald eagles are known for their fantastically acrobatic aerial mating rituals, it is actually the nest-building that cements the bond between mates, building on the same nest season after season. Bald eagles are among the estimated 95% of birds that are socially monogamous – meaning they cooperatively raise their young over the course of a mating season and in most cases, will return to the same nest and mate year after year. One nest, used by an eagle pair for over 3 decades, measured 9 feet across, almost 12 feet high, and was estimated to weigh over 2 tons. While genetic testing shows that they may engage in a little fling on the side now & then, known as “extra-pair copulation,” only several years of unsuccessful clutches or the death of one eagle will break up these super-couples.
4. Sandhill Cranes
Another bird renowned for their elaborate mating dances, the sandhill crane is also known as a symbol of long-term fidelity. Bonded pairs call in unison, spreading the word that they are in a committed relationship. During the massive breeding-ground migrations in the spring, their synchronized “kar-roo” is thought to be a bonding activity, kind of like Ginger Rogers and Fred Astaire dancing and singing their way across the stage. Unlike Fred & Ginger, crane pairs will stay together until one of them dies, even if they have a couple nests that flop. Philandering among crane pairs is so rare that when a single extra-pair copulation event was witnessed in 2006 it was big news; in fact it was the first one ever documented.
3. Black Vultures
For black vultures, enforcing monogamy is a community affair. These ominous birds seem to be deeply serious about their commitment to a chosen partner. The pair will hang out together year-round and share parenting duties. Individuals caught engaging in extra-pair copulation will not only be attacked by their mate but by neighboring vultures as well. Genetic study of 17 different vulture families found no evidence of extra-pair fooling around, giving new meaning to the phrase “It takes a village…”
2. Prairie Voles
Mammals – rodents in particular, are not necessarily known for their fidelity. But the little prairie vole is a notable exception. Once they have lost their virginity, males will prefer to mate exclusively with that female, even going so far as to attack other females. Scientists have traced this behavior to a hormone in the brain, which triggers lasting bond formations and aggression towards potential home-wreckers. Once mated, these “high school sweethearts” share parental duties, groom one another, and appear quite affectionate. When presented with “unfamiliar, virgin females” in the wild, less than 10% of male voles succumbed to the temptation. Even more unusual, less than 20% of committed voles sought out a new mate if their partner died.
1. Diplozoon paradoxum (parasitic worm)
As unattractive as it sounds, this worm takes the prize for most committed among Nature’s couples. I’ve spared you pictures of this particularly homely couple. This fish parasite practices an extreme form of monogamy. Individuals meet as virgin adolescent larvae and literally fuse together at their midsections. Sexual maturity is not reached until the worm fuses with a mate. Once fused, they remain together until they die sometimes several years later, when even then they are not parted. As Dr. Barash, a professor of psychology at the University of Washington in Seattle noted in an article in the New York Times, “That’s the only species I know of in which there seems to be 100 percent monogamy.” The only heartache here is in the unfortunate fish that hosts this epic romance.
Sarah Shimek is the education coordinator for the River Bend Nature Center, a 501(c)3 non-profit organization in Faribault, Minnesota that specializes in nature and environmental education. The Nature Center property includes 743 acres of original and restored natural lands with over ten miles of trails that are open to the public 365 days per year. River Bend Nature Center relies on donations and memberships to fund its operations, please join and give today. Contact us at email@example.com or 507-332-7151.