Novel baseline data on leopard seals, the mysterious apex predators of Antarctica – Science Daily

Baylor University marine biologist Sarah Kienle, Ph.D., has always been fascinated by leopard seals. These prehistoric, reptilian-looking seals are often portrayed as scary villains in movies such as “Happy Feet” and “Eight Below,” but little is known about their basic biology. The combination of the extreme climate in Antarctica, the species’ solitary habits and their lethal reputation makes leopard seals one of the most difficult top predators to study on Earth.
In a first-of-its-kind study funded by the National Science Foundation awarded to professor Daniel Costa (lead PI; UCSC), associate professor Stephen Trumble, Ph.D. (Baylor), professor Shane Kanatous, Ph.D. (Colorado State University), wildlife biologist Mike Goebel, Ph.D. (NOAA), and professor Daniel Crocker, Ph.D. (Sonoma State University), the PIs and Kienle (a graduate student and postdoctoral researcher at the time) set out with one shared goal: to learn more about leopard seals. Over the course of two years, the research group studied 22 leopard seals off the Western Antarctic Peninsula, an area rapidly warming and changing. They weighed and measured each seal and followed each seal’s activities and dive patterns using satellite/GPS tags.
In the study published in Frontiers of Marine Science — “Plasticity in the morphometrics and movements of an Antarctic apex predator, the leopard seal” — Kienle (first author) and the team documented the flexible behaviors and traits that may offer leopard seals the resilience needed to survive the extreme climate and environmental disturbances occurring around Antarctica.
This study greatly increases our understanding of leopard seals’ life history, spatial patterns and diving behavior,” Kienle said. “We show that these leopard seals have high variability (or, flexibility) in these different traits. Across the animal kingdom, variability is vital for animals adapting and responding to changes in their environment, so we’re excited to see high variability in this Antarctic predator.”
Among the research team’s discoveries detailed in the journal article:
Adult female leopard seals are much larger than adult males; in fact, females are 1.5 times larger and longer.
From the movement data, female leopard seals spent more time “hauled out” — or coming out of the water to rest on ice or land — than males.
Male and female leopard seals swim short and long distances in both coastal and open-ocean habitats.
Leopard seals of both sexes are short, shallow divers — diving to an average of 30 meters and taking three-minute-long dives.
“It’s interesting to see such variation [in movements and dive behavior] in a relatively small number of animals. To me, this means that leopard seals are highly flexible in their movement patterns, and that’s a really good thing in terms of adapting to changes in your environment,” Kienle said.
What’s next for this team of leopard seal biologists? Kienle said the team continues to analyze additional data from these same 22 leopard seals for publication. Kienle also is excited to compare how the leopard seals from this study compare to other populations of leopard seals across the Southern Ocean.
“I have so many more questions, and I’m excited to continue learning about leopard seals for years to come. There’s so much more to discover about this incredible Antarctic predator,” said Kienle, who leads the Comparative Ecophysiology of Animals Lab at Baylor that focuses on understanding how different animals work in the context of their environment.
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