Mating Behaviors Of Different Sized Sharks
Scientific Study on the Small-Spotted Catshark 2013:
Sexual Dimorphisms in the Dermal Denticles of the Lesser-Spotted Catshark, Scyliorhinus canicula (Linnaeus, 1758) by Neil Crooks, Lucy Babey, William J. Haddon, Adrian C. Love, Colin P. Waring.
Scientific Study on the Oceanic Whitetip shark July 2019:
Reproductive timing and putative mating behavior of the oceanic whitetip shark Carcharhinus longimanus in the eastern Bahamas by Brendan S. Talwar, Mark E. Bond, Sean Williams, Edward J. Brooks, Demian D. Chapman, Lucy A. Howey, Ryan Knotek, Jim Gelsleichter.
Scientific Study on the Whale Shark 1999-2014:
Evidence that St. Helena island is an important multi-use habitat for whale sharks, Rhincodon typus, with the first description of putative mating in this species by Elizabeth Clingham, Judith Brown, Leeann Henry, Annalea Beard, Alistair D Dove.
What Is Sexual Dimorphism?
Sexual dimorphism, which is the distinct difference in size and appearance in the sex of the animals. For example, females are usually larger than males in most shark species. But, have you ever wondered if an overall smaller shark species’ reproductive habits differ from a much larger shark species because of their size?
OVERVIEW
This study will utilize the observations and results from three previous scientific studies to form an overall conclusion about the mating behaviors of the small-spotted catshark, Oceanic whitetip shark, and Whale shark in relation to their varying sizes. For this comparison on mating behaviors in relation to sexual dimorphism, I will be examining each scientific study, and drawing conclusions from the information provided.
WHY DO THIS STUDY?
Learning about the mating behaviors of different sized sharks is important in understanding the ecological impact of each species, as well as aiding in conservation efforts.
LEARN MORE ABOUT EACH STUDY
Small-Spotted Catshark
- Topic: Sexual Dimorphism
- Reproduction: Lay Eggs
- Behaviors: Male wraps himself around female, biting, females seeking refuge in shallow waters.
- Size of pup: 3.5-4 in/8-10 cm
RESULT: This study explores the thickness of the dermal layers of female and male cat sharks is determined by their mating behaviors. Six mature adults were captured and their skin was measured and photographed to examine the dermal layers. They found that body length did not affect dermal layers, but sex did. Females had a thicker dermal layer, most likely due to biting by the males during mating.
Oceanic Whitetip Shark
- Topic: Mating Behavior
- Reproduction: Live Birth
- Behaviors: Synchronous swimming, parallel swimming, following, biting, shielding, nosing.
- Size of pup: 18-22 in/45-56 cm
RESULT: This study investigates the reproductive timing and mating behavior of the Oceanic Whitetip shark. Observations for this study took place at Columbus Point in July 2019. They observed several mating behaviors and determined that mating typically occurs in July. They also discovered a new mating behavior, called circle-back.
Whale Shark
- Topic: Mating Behaviors
- Reproduction: Live Birth
- Behaviors: Mating behaviors include males following the females, males flips over to position himself as he gets closer to the female, belly to belly contact on the surface.
- Size of pup: 16-24 in/40-60 cm
RESULT: This study examines the mating behaviors in Whale sharks, which has been rarely witnessed. Observations for this study were recorded between February 1999 to 2014 in St. Helena Island. From 2005 to 2007, they recorded observations of rare mating behaviors and pregnant females.
MY CONCLUSION
From my findings, it seems that shark species of differing sizes share similar mating behaviors, with a few exceptions. The largest fish, the Whale shark, has a very different mating process than the Small-spotted Catshark, which I attribute to difference in size and sexual dimorphism.
Small-Spotted Catsharks are one of the few shark species that live separated by gender unless they are mating. Females are known to avoid mating by hiding in the shallow waters, in crevices or rocks (Crooks et al., 2013). This may be because they spend most of their lives away from males, so it is in their nature. The Small-Spotted Catshark mating is quite different from whale sharks, perhaps due to their extremely small size. At only 2 to 3 feet, these sharks mate in shallow waters. Since most females display avoidance behaviors, mating is a rather chaotic event compared to whale sharks. The males wrestle the females, and there’s a lot of trashing. Their small size allows the males to clasp on to the females and stay attached during mating which could be difficult if they were larger and engaged in a lot of movement.
Oceanic Whitetips displayed numerous mating behaviors that are shared with other species except for circle backs. This is where the male will circle the female, displaying his fins and producing low frequency sounds. This lets the female know they are ready to mate. This mating behavior is not common for shark species. In fact, the study recorded that this behavior is “newly observed” for this species (Talwar et al., 2019).
Whale Sharks were perhaps the most fascinating to learn about since we know very little about their reproductive habits and behaviors. The observations at St. Helena were monumental, with the first sightings of mating behaviors of whale sharks and apparent pregnant females (Clingham et al., 2016). Whale sharks seem to engage in similar mating behaviors such as following. It is also interesting to note that mating for this species takes place on the surface, something uncommon in other species. This may also be correlated with their size.
In terms of size, there are two mating behaviors that I found to stand out. Whale sharks seem to position themselves for mating in quite a unique way, which I haven’t quite seen in other species. This has caused me to draw the conclusion this may be due to their large size. Male whale sharks were observed swimming on their backs, belly facing up, right before they made contact with the female. This is so they can make belly to belly contact, which is how they engage in reproduction. In other shark species, I usually see them vertical or entangled with one another. However, whale sharks seem to mate by having the male seamlessly slide under the female, so they can keep swimming. I believe this may be due to their size. Since they are the largest fish, it may be difficult for the male to stay attached to the female if they are moving around or changing positions.
Article written by Liel Shachr, University of Florida, B.S. Natural Resource Conservation, Political Science