Yes, that’s not unusual for a mated pair of ponies to change partners when they are introduced to an aquarium with a group of seahorses and suddenly have other options to consider.
In fact, Tammy, I find that seahorses are often not at all monogamous in captivity when they are kept in groups and have a choice of partners.
Captive-bred seahorses are far-different animals than their wild conspecifics in that respect when it comes to their breeding habits. They are raised at far greater population densities than wild seahorses ever experience, and are accustomed to living in close proximity to others of their kind and to having a selection of possible partners to chose from when mating. As a result, farm-raised seahorses are highly social animals and appear to be far more gregarious and more promiscuous than their wild counterparts.
Captive-bred seahorses do indeed pair bond, but the attachments they form are by no means permanent. A couple may stay together for a single mating or for several breeding cycles (Cozzi-Schmarr, May 2002). When provided with a choice of mates, however, they are apt to swap partners for no apparent reason after any given mating, and generally seem to enjoy exploring different pairings (Cozzi-Schmarr, May 2002). One sees this all the time when adding new specimens to an established tank. The introduction of the new arrivals triggers a renewed flurry of greetings and other interactions and kicks the general activity level up a notch as all the seahorses reassess the shifting social dynamics of the herd and check out prospective new mates. Chances are great the next breeding cycle will see some new pairings.
It has certainly been my experience that when seahorses are provided with a group of potential mates to choose from, they will take advantage of that situation to try different pairings. It is very possible that this polygamous behavior may simply be an artifact of captivity, the inevitable result of keeping seahorses in small closed-system aquaria where they cannot maintain anything approaching the large territories they are said to enjoy in the wild. But it is a fact that polygamy is the norm for seahorses in the captive environment when they are maintained in groups, and that monogamy tends to break down in such situations.
Interestingly, it is fairly easy to predict which couples are likely to remain together and which pairs are apt to wind up with new partners next time around. Pairs that continue to conduct daily greetings in the aquarium are very probably going to re-mate when the male delivers his next brood. But all bets are off when a fickle filly proceeds to flirt with males other than her mate while he is carrying young. She is liable to bestow her eggs with one of the other available males when the next breeding cycle begins. It is the female who initiates daily greetings, and if she chooses not to renew her bonds with her current mate each morning, it’s a very good sign that this mare is moving on to greener pastures.
Eventually, these brazen broodmares are apt to give all the studs in the stable a roll in the hay. Presented with the option, it is sound genetic policy to diversify and try different combinations of genes. I suspect the only reason this doesn’t occur more often in the wild is a lack of opportunity.
The behaviors you noticed are typical of rival males competing for mates, and indicate that both of your stallions are mature individuals with a healthy interest in mating and lots of energy to burn. This sort of intraspecific aggression is completely normal and is generally harmless, Tammy – nothing that you need to be overly concerned about.
However, it can disrupt courtship and delay breeding until the two adversaries resolve the matter and a dominant pair emerges from the trio of individuals.
When it comes to competition for mates, the females are generally far more passive-aggressive in how they go about it. In the aquarium, both males and females compete for mates, but there is a big difference in the way they interact with their potential rivals. Females tend to compete with one another passively, each trying to outdo the other and be the first to attract a mate simply by increasing the intensity of their courtship activities and displays. Their competitive behavior is therefore normally directed at the eligible males rather than any rival females. Males, on the other hand, compete much more actively and much more antagonistically. Their behavior is often aimed directly at their rival(s) and includes aggressive behaviors such as tail wrestling, headbutting, and snapping or sparring, which are almost never seen in the fairer sex. In other words, females tend to respond to the presence of nearby rivals by getting more flirtatious, whereas males often react to potential rivals by getting surly and carrying a testosterone-induced chip on their shoulders.
In general, male seahorses compete more actively and aggressively than females, and basically try harder to get pregnant than female seahorses try to give their eggs away. In the kinky world of seahorse sex, the boys still chase the girls, even though it’s the boys who get pregnant as a result!
And when two or more evenly matched young studs are butting heads and aggressively contending for the right to reproduce, the cutthroat competition often brings out surprising, seldom-seen behaviors in Hippocampus. This includes tail wrestling and snapping or headbutting, just as you have seen, Tammy.
Tail wrestling is self-explanatory but snapping is a little more complicated to explain. Sparring males will attempt to give their opponents a good head butt with the barrel of their snouts. This behavior is known as “Snapping,” an aggressive maneuver in which the attacker stretches out its head and flicks its snout against its rival with a violent snap, thus delivering a nasty blow to the adversary. The snap is often aimed either at the opponent’s eye or gills — particularly sensitive areas — and the force of a well-directed snap can knock the unfortunate recipient reeling.
Snapping is normally exclusively a male tactic, and is almost never seen among the female seahorses. If you are pairs of ponies have only recently been introduced to one another, it’s likely that they are still sorting out the shifting group dynamics and social hierarchy of the new herd, Tammy. Domesticated seahorses often do work out a dominance hierarchy of sorts, and that’s probably all that is going on right now with your seahorses.
In this case, it’s not surprising that two of the stallions are competing for the attention of the largest female, since size is one of the characteristics that is prized in a mate. A larger female can provide more ripe ova than a smaller female, so the studs are naturally attracted to the big girls. Sooner or later, the stallion should sort things out and one of them will be able to assert his dominance, or the large female will settle the issue for them by selecting one of the males as her preferred partner.
In the meantime, there’s no need for you to be worried about the sparring and jousting of the rambunctious males, Tammy. They are just working off a little excess energy (and perhaps a little sexual frustration) and will do no lasting harm.
It’s important to understand that competition for mates is highly ritualized in Hippocampus. Let me repeat: the idea is to assert dominance, not inflict bodily harm. Tail wrestling and snapping are forms of ritual combat — little more than glorified shoving matches and tug of wars — with clear-cut submission signals that are always honored. They seldom do any real damage and the combatants are so well protected that serious injuries are virtually unknown when these armor-plated adversaries throw down the gauntlet.
In short, intrasexual competition for mates can sometimes disrupt a budding courtship momentarily, but it’s usually nothing to be concerned about and is always extremely interesting to observe. In short, I don’t think you need to intervene, Tammy, and the situation should soon sort itself out without any harm being done. So for now just enjoy the show and keep an eye on things to make sure the aggression doesn’t get out of hand. (It rarely does.)
With that being said, it would not be a bad idea to introduce another large female into your aquarium to and take some of the pressure off of the big mare that now seems to be the center of all the attention, providing your aquarium is large enough to safely support another adult individual. Adding a new good-sized female would very likely result in more courting and renewed mating attempts, Tammy.
The genetic imperative to reproduce is very strong in Hippocampus, to say the least. For example, solitary males often go through the motions of courtship when there are no other seahorses present in their aquarium (Abbott, 2003). They may court their own reflection and sometimes even direct their courtship displays toward their keepers (Abbott, 2003). If no females are present, over-stimulated stallions will sometimes soothe themselves by basking in the air stream from an airstone, content with the tactile stimulation provided by the gentle barrage of bubbles. They may even flirt with inanimate objects. If all else fails, a hitching post may actually suffice as a suitable surrogate when no better alternative is available (Abbott, 2003)!
Same-sex courting displays (both male and female) are also common when no member of the opposite sex is present. Under such circumstances, these passionate ponies are not picky about their partners — males will dance with other stallions and frustrated females will sometimes flirt with other fillies (Abbott, 2003)!
Captive-bred seahorses are far more social and gregarious than their wild conspecifics, so it’s not surprising that cultured seahorses are particularly irrepressible in that regard. They seem to court constantly and the urge to procreate dominates their lives. If given a choice, they are apt to change partners often, and courtship, flirting and dancing are the activities that consume their days. Long before they are sexually mature, juvenile males will spend hours dancing with one another, just horsing around, practicing their moves and perfecting their technique for the real thing to come. Likewise, mature males often compete actively and aggressively with one another through harmless pouch displays and tail-wrestling tug-o-wars whether or not there is a female nearby to appreciate their efforts.
As Carol Cozzi-Schmarr of Ocean Rider, the premier aquaculture facility in Hawaii, puts it, “As far as mating is concerned, it is important to understand that because these sea horses are farm raised and therefore “domesticated” they will be breaking a lot of the rules previously established for wild caughts. They will require less horizontal as well as vertical space and they no longer tend to be shy or picky! In other words they will show off to and mate with whomever they can, even if it means leaving behind the sea horse they mated with last time! It does not matter if their selected partner appears too short or too tall or of a different color or even of the same sex!! They want to dance and court more than anything else (Cozzi-Schmarr, May 2002)!!”
Best of luck with your amorous stallions, Tammy! Here’s hoping that their persistence eventually pays off with some successful mating attempts.
Pete Giwojna, Ocean Rider Tech Support