The sun is shining, the snow is melting, and some of the animals here at the SeaLife Center are displaying their exuberant breeding plumage, or showing off their massive increase in body size. These changes signal that breeding season is upon us in Alaska, and as caretakers and scientists, we are either trying to learn more about the beautiful process of reproduction or we are caring for animals during this highly hormonal period of their lives. Either way, animal care professionals and researchers together find breeding season fascinating (check out previous blogs for specifics here, here and here!)
Take a moment to consider the diversity of life in our oceans, and when you do, you will notice there are a variety of gender roles within these processes that are far from heteronormative relationships.
Charles Darwin’s hypothesis of sexual selection, which he proposed 150 years ago, depends on the struggle of males to access females. This is a competition between members of the same-sex (usually males) for access to mates (usually females), while members of one sex, usually females, choose members of the opposite sex. For a long time this was thought to be the primary system in nature, but as scientists looked closer at reproduction and gender roles in the animal kingdom, they found observations of non-traditional gender roles. In addition, as we look at ourselves, there is a broad spectrum of variation in gender roles and couplings! We are also a part of this diverse animal kingdom and our species also displays these different variations in gender and relationships. The LGBTQ community represents lesbian, gay, bisexual, transgender, and queer populations. Same-sex families raising children, people who are single utilizing in vitro fertilization to have children, the process of gender transformation, and polygamous relationships, are all examples of successful progressive lifestyles that are becoming more socially and politically accepted. Even though they are being expressed more in our communities, they have been a part of human behavior and the human condition as long as there have been humans.
Non-binary gender variation (genders outside male and female, ie. hermaphrodite) and homosexual behavior in animals are now attracting more research and questions about the reproductive process! We even see this right here at the SeaLife Center!
OYSTERCATCHERS
In the bird habitat, early in the morning you may hear a very high-pitched “wheeps.” On a good day, you can hear these calls up to a half-mile away! This is the loudest avian vocalization in the collection and it is a part of the oystercatcher courtship display.
Below is a video of American oystercatchers, similar to Alaska SeaLife Center’s black oystercatchers, vocalizing!
During breeding season, it’s common for a male and female to pair off to mate. Both will dig out and guard a scrape, more commonly known as a nest, in the pebbles on a beachscape. The female will lay one to two eggs and both the male and female take part in building the nest and incubating the egg.
Roxanne and Cadet are two oystercatchers that are housed at the Alaska Sealife Center. They have been paired together since 2006, and they are both females. There has been an attempt to introduce a male to the pair, but this wasn’t successful and the male was rejected. Both Roxanne and Cadet have laid eggs and they both help build the scrape and incubate the egg. Puffins and other seabirds like Albatross have been observed forming same-sex pairings as well. Roxanne and Cadet are currently residing at ASLC where you have a chance to see them in the bird habitat!
Roxanne defending her nest this summer 2018. She’s laid 3 eggs. Cadet seems to be doing most of the territory defense, though it’s only been 2 days of incubation so far.
SPOTTED SHRIMP
When visitors to the Alaska SeaLife Center wander towards the touch tank, they will encounter spotted prawns–members of the Pandalidae family. This shrimp species, along with several others, are sequential hermaphrodites. What does this mean? Sequential hermaphroditism is when an animal changes sex during its life cycle. If it changes from male to female, it is “protandry”. If it from female to male, it is “protogyny”. Spotted prawns are protandry–they begin as males and at some point change their sex to female. What might be the benefit of this strategy? Leave your thoughts in the comments!
HAIRY TRITON SNAIL
When you go to the Discovery Pool at the ASLC, you will find a hairy triton snail! You may find this snail laying eggs in a beautiful circular pattern on rocks or any hard surface. These snails don’t need another snail to reproduce and can do it all on their own! This is called asexual reproduction. They often lay eggs, so come see if you can spot them!
SEA ANEMONES
We have several species of sea anemones at the ASLC that can also reproduce asexually. This can happen in one of two ways, either by binary fission or by pedal laceration. Asexual reproduction by binary fission is when an organism splits into two separate individuals. During pedal laceration, a grown anemone moves away from an area, which could be due to change in habitat or to escape predation, it leaves behind fragments of its pedal disc. From these fragments, a new anemone is formed by regeneration.
To make things even more interesting, sexual reproduction can also happen and there are several species of sea anemones that are hermaphroditic (the anemone has female and male reproductive systems).
***
These are just a few examples, but clearly it is amazing in the animal kingdom how much variation there really is and how it can be nature’s most extraordinary adaptation!
If you’re interested in learning more, CHECK OUT THIS WEBSITE where you can explore the mating behavior of 33 different animals, explained in the form of adorable cartoons by “Humon Comics”:
Another great resource for a more in-depth look into breeding, gender and the animal kingdom is this article by the BBC that is quite compelling on sexual revolutions.
Written by: Juliana Kim, Mammalogist
Expert information provided by ASLC Husbandry staff: Aquarium Curator Richard Hocking, Aquarium Manager Jared Guthridge, Aviculturist Caitlin DeGrave, Aviculturist Amy Beich
Feature image taken under NMFS Permit #18438
All other photos were taken at the Alaska SeaLife Center from public viewing locations.
Excellent article! I had no idea that gender roles were as diverse in the animal world as they are for humans. It gives great weight in the ‘nature versus nurture’ argument, no?
Thanks for sharing!