Science Update

Yesterday, we collected samples from 44 incubation bottles. It was a long day of filtering, labeling and storing samples. This is day 10 of Incubation 3, so we will not be collecting samples from these bottles today. Instead, the science team will work on data entry, data analysis, individual experiments and packing samples. We will also gather for a science meeting later this afternoon to hear from our head scientists about current data trends and additional background information related to the research cruise. I enjoy these science meetings because it is an opportunity to learn more about the thought process behind certain decisions and to hear more from each member of the science team regarding their contributions.

Ice Update

Our forward progress has definitely improved in the last 12 hours. More cracks are appearing in the ice as we continue to work our way through the snow and ice. Open water is now in sight (approximately 6 miles away as of 2100 last evening). Although the process is slow, we are moving and will eventually reach open water, and our next sampling station.

Another Check on the Bucket List

From the moment I learned that I would be traveling to the Southern Ocean and the Antarctic Peninsula I had one goal - see a leopard seal. Why? First, this is the only place that you can see leopard seals (to my knowledge, they are not held in captivity) and second, they are intelligent, powerful animals that I have always found intriguing (aka they are AWESOME!). From the moment I boarded this ship, I made it known that I wanted to see a leopard seal. A standing order was in place with everyone aboard to notify me if there was a leopard seal sighting. Earlier this week, I got a knock on my cabin door followed by four words: leopard seal, starboard side. Music to my ears!! I took about 50 pictures of this one seal and spent the rest of the time simply watching this impressive animal. Another truly amazing experience in Antarctica!

Leopard Seals Hydrurga leptonyx

Leopard seals, along with the orca (or killer whale) are considered to be the top predators in the Antarctic ecosystem. As adults, leopard seals primarily eat penguins, but have also been known to feed on krill and other species of seals. These carnivores have long fore-flippers and powerful back and shoulder muscles that allow for speed and agility while chasing penguins below the surface of the water, or on ice. Leopard seals (also known as sea leopards) have long (2.5cm/1inch) canine teeth at the front of their mouth to aid in their attacks. The molars near the back of the mouth, while sharp enough for chewing and tearing, are able to interlock like the teeth of the crabeater seal in order to strain krill from the water. It is thought that younger leopard seals may rely on krill for food earlier in life before they master their hunting techniques.

Another interesting adaptation for the leopard seal is referred to as counter-shading. This coloration pattern is a common form of camouflage in the animal world. In counter-shading, the dorsal (top) portion of the body is dark while the ventral (bottom) portion of the body is lighter in color. This is true for both predator and prey animals.

Counter-shading
The dorsal (back) of the leopard seal is dark in color. This helps to camouflage the seal when hunting for prey deeper in the water column. The long foreflippers help the leopard seal make sharp turns in the water when chasing prey.

In the image above, there is a noticeable color difference between the dorsal side (back) and the color of the (ventral side) belly of the seal. If the leopard seal is swimming below a penguin or group of penguins, the dark coloration of the dorsal surface blends in with the darker waters at depth. If the leopard seal is swimming above its prey, the lighter ventral surface mimics the lighter areas in the surface of the water, especially if the sun is shining. This counter-shading may provide additional time for predators to stalk their prey, or for prey to escape before the predator takes notice.

Leopard Seal Facts:

  • Length: ~8.5-12ft (females are slightly larger than males)
  • Weight: 500-1400lbs
  • Named for coloration on throat: mostly white area with black spots
  • Breeding season: November to January (single pups are born in May or June)
  • Large, reptilian head (distinct shape from other seals in area) with v-shaped nostrils that appear to point upward instead of forward like other seals in the area
  • Can be detected underwater using a hydrophone (underwater microphone) because of the distinct trills and moans that are produced by leopard seals. Males actually produce distinct, individual 'songs' during the breeding season.
  • Usually solitary (do not form groups)

Lazy leopard seal
An initial look at a leopard seal shows a number of distinct features: reptilian head, sleek body and long foreflippers. This leopard seal remained in this position for most of the sighting.

Leopard seal head lift
The leopard seals lifted its head, presumably to look at the ship. From this angle, you can see the characteristic up-turned nose of the leopard seal and the mouth line that is usually described as a sly smile.

As we watched this leopard seal, it remained on the ice floe for a long period of time before moving into the water. The seal did not make any attempts to vocalize at the ship and it did not show any aggression towards the vessel. There are many stories of leopard seals behaving in a aggressive manner towards large ships (even those as large the RVIB Palmer)! Other stories include leopard seals hunting penguins, or swimming along the edge of the ice looking for food. There are other stories that show another side to leopard seals - including behaviors interpreted as teaching. Science team member Dr. Randie Bundy enjoyed the leopard seal story in the TED talk by Paul Nicklen entitled: Animal Tales from Icy Wonderlands. Check it out - you won't regret it!

Love From Little Landlubbers

Speaking of wildlife - I have a few penguin pictures to share. The drawings were made by Asha and Eric from Chicago, IL. Thank you both!

Penguin Patrol
Thank you, Eric, for such a great picture of penguins on patrol!

Penguin family
Asha created a penguin family - complete with a little grey fledgling! Thanks Asha!

Author
Date
Weather Summary
Overcast with good visibility
Temperature
2C/36F
Wind Speed
10-15 knots
Wind Chill
-6C/21F

Comments

Cara Pekarcik

I did not read anything about this during my research.  It is possible that they may weigh less during the winter when there is less productivity, but I cannot say for certain.

From: PolarTREC
To:
Sent: 10/21/2016 9:23 AM
Subject: Re: Victoria H, Block G commented on 7 October 2016 TGIWF #4

(

Cindy Zheng

Is it easy to confuse the leopard seals with other seals?

Vivian Tran

Hello Mrs. Pekarcik! I loved your live viewing (I know it's a little bit late but I still want to say how great it was). So, why do the leopard seals have two different breeding seasons?

Cara Pekarcik

From a distance, sure.  As you approach the seals, the head shape and coloration pattern of the leopard seal can help to identify the species.

From: PolarTREC
To:
Sent: 10/23/2016 12:20 PM
Subject: Re: Cindy Zheng commented on 7 October 2016 TGIWF #4

(

Cara Pekarcik

Hi Vivian - I apologize if my description was confusing. The breeding season listed indicates the mating season. The pups are born later
after a gestation period (pregnancy). Sorry!

On 2016-10-11 10:05, PolarTREC wrote:

SheilaB Block E

How long do leopard seals stay out of the water before going back in? Why do they do it, other than air?

haysha agudo

Why is the leopard seal solitary? Do they become violent around other seals?

Cara Pekarcik

Sheila - I don't know that there is a specific amount of time that any seal stays out of the water.  Most seals move out of the water onto sand, rocks or ice in order to rest.

From: PolarTREC
To:
Sent: 10/20/2016 6:53 AM
Subject: Re: SheilaB Block E commented on 7 October 2016 TGIWF #4

(

Cara Pekarcik

Many animals are solitary.  It could be for a number of reasons - aggression, ability to catch more prey, etc.

From: PolarTREC
To:
Sent: 10/20/2016 7:25 AM
Subject: Re: haysha agudo commented on 7 October 2016 TGIWF #4

(

Reina C, Block B

Hi Mrs. Pekarcik; the last picture of the seal is funny because it's just lazily lying there. It's almost as if it's saying, "Hey what's going on?" Anyway, these seals are not in captivity to your knowledge...are they in danger of being extinct? Also, what makes you so interested leopard seals? Is there a story behind your interest?

Victoria H, Block G

Does the time of the year affect the seals' weight?

Cara Pekarcik

Hi Reina - leopard seals are not endangered. My interest simply stems from the fact that they are a well-adapted predator and they are not
seen by many. I have always been interested in seeing one, but there is
no real back story.

On 2016-10-08 18:24, PolarTREC wrote: