Seahorse divorce? Of course, of course!

Abstract

Long-distance, monogamous relationships are hard, regardless of how much you love your partner. Without seeing and interacting with them regularly, you may drift apart and fall for someone else. However, frequent and open communication can help keep the spark alive, even over a distance; I FaceTime my partner every night when I'm in the field. But other monogamous animals do not have cell phones or laptops; they cannot text or Zoom about their day or complain about their terrible co-workers. Without these tools, how robust are their relationships over periods of separation?To figure this out, a team of scientists from the Chinese Ministry of Agriculture and the Chinese Academy of Fishery Sciences, led by Tingting Lin, looked at lined seahorse relationships. Seahorses form monogamous pairs and mate with their partners time after time, with the males tasked with carrying around the fertilized eggs. To strengthen their bonds, paired seahorses don their finest colors and participate in synchronized swimming every day in an act known as a daily greeting, which makes my day-to-day efforts of FaceTiming my partner seem rather poor. When seahorse pairs were kept together in the lab and were able to perform their daily ritual, Lin and the team found that females usually remained faithful to their partners, even in the presence of the most attractive male seahorses, illustrating their strong bonds. However, if their male partners were injured or sick, some females sought out new partners that were healthier and better able to care for their eggs, even while their current mate was pregnant. Apparently, ‘in sickness and in health’ means nothing to seahorses.After they established that seahorse relationships tend to be strong, the team tested whether they are resilient enough to endure a break. First, Lin and the team allowed male and female seahorses to court each other, pair and mate. Then, they separated the partners for at least 12 days and introduced new males to the females, whereupon the females lost their faithfulness and mated with the new males. But it did not stop there. The scientists then separated the new male partners from the females for at least 4 days and then presented the female seahorses with the choice of either their former partner, the recent partner or a new mystery seahorse all at the same time, to see which male the females would select.But instead of preferring one of her previous partners, the female seahorse selected her new partner at random. After only a few days of separation, females showed no preference for previous partners over a random male seahorse. Even a short period of separation seems to be long enough for female seahorses to either completely forget their previous partners and the offspring they shared, or drift apart, like, well, a seahorse without seagrass to hold onto.While seahorse divorce may seem like a sad subject, it may have its benefits. If monogamous animals pair with poor quality mates, their bond, once formed, may be too strong for them to realize that their partner isn't appropriate, preventing them from seeking out better quality mates. Periods of separation may allow these animals to reassess their partners, giving them an opportunity to get out of bad relationships. So, if you do not want to end up like divorced seahorses, make sure to communicate well and/or dance in circles wearing your fanciest attire every morning.