Durham University
Mother seals' personalities determine whether they will frequently check on their pups to make sure they are safe, according to the researchers. In the above photo, an attentive gray seal mother checks up on her pup.
updated 11/29/2011 2:06:11 PM ET 2011-11-29T19:06:11

Gray seals have widely varying mothering styles, with some inattentive seal moms barely checking up on their pups at all, even if they sense a threat to their safety, a new study on seal colonies in Scotland finds.

The scientists involved in the study contributed the various parenting styles to personality differences among the wild gray seals (Halichoerus grypus). Their personalities determine how these marine mammals respond to different situations and, in turn, the extent to which they guard and care for their young, according to the study.

Over the course of two years, the researchers observed seals in their natural habitat on the Scottish island of North Rona during their breeding season, which takes place between September and November. Monitoring the behavior of the seals for two years was possible because many seals return to the same site to breed, and the researchers were able to identify particular seals by their individual fur patterns.

Durham University
The above gray seal mother is aggressively protecting her pup from an intruder.

To study how the seals reacted to external stimuli and potential threats, the team fitted a remote-controlled vehicle (RCV) with a video camera and programmed the vehicle to approach the seals. The researchers conducted 11-minute-long tests on 28 females, during which the vehicle approached the seals while emitting a wolf call.

The results showed that the seals' responses ranged from completely ignoring the RCV's presence to being aggressive and pushing it with their muzzles. The team gauged the seal mothers' responses by recording how many times the moms checked on their pups during a specific time period. Females tend to stay with their pups and conduct "checks" on them by raising their heads off the ground and moving it in the direction of their young in order to verify the pups' well-being.

"We found that some seal mothers are very watchful when something potentially threatening approaches them, while other mums barely check their pups at all," study researcher Sean Twiss of Durham University said in a statement. "Why female gray seals express individually consistent patterns of pup checking is unknown."

Durham University
An alert gray male seal looking out for signs of danger.

Twiss added that you'd expect the moms "to change their behavior according to the situation, but the non-attentive mothers remained inattentive."

The researchers also used the RCV to check the male seals' responses, finding a similarly wide range of "fathering," with some seals rapidly retreating while other males approached the RCV in a challenging way, such as with their mouths open, which seals view as a threat.

"Our findings show that there is no such thing as an average seal," Twiss said. "Individuals behave differently and do so consistently."

Among both male and female seals, responses were not linked to factors such as age or size. The researchers noted that further studies are needed to better understand the nature and ecological consequences of individual differences in behavior.

The study was recently published in the journal Marine Mammal Science, and its findings will be presented at the 19th Biennial Conference on the Biology of Marine Mammals in Tampa, Fla., which started Sunday and continues through Friday.

You can follow LiveScience writer Remy Melina on Twitter @remymelina. Follow LiveScience for the latest in science news and discoveries on Twitter @livescience  and on Facebook.

© 2012 LiveScience.com. All rights reserved.

Explainer: Zoo babies

  • In zoos all over the world this year, little bundles of joy were brought into the world, causing zoo-goers to coo. From the furry to the scaly to the underwater dwellers, OurAmazingPlanet takes a look at a few of the cuties that joined the animal kingdom in 2010.

  • January — Western Lowland Gorilla Baby

    Image: Western lowland gorilla mom and baby
    Mehgan Murphy/Smithsonian National Zoo

    On Jan. 10, a baby western lowland gorilla was born at the Smithsonian’s National Zoo. Staff estimate the baby was born at approximately 1:45 pm to 26-year-old female Mandara and 16-year-old Baraka. The newborn represented the seventh successful gorilla birth for the Zoo since 1991.

    In this image, taken on Feb. 2, 2009, the great ape keepers at the zoo let Mandara and her 3-week-old baby outside to enjoy the mild weather. Due to deforestation and hunting, clouded leopards are listed as "vulnerable to extinction."

  • February — Clouded Leopard Cubs

    Image: Clouded leopard cubs
    Mehgan Murphy/Smithsonian's National Zoo

    February — Clouded Leopard Cubs

    A clouded leopard at the Smithsonian's National Zoo’s campus in Front Royal, Va., gave birth to a genetically valuable litter of two cubs on Valentine’s Day — Sunday, Feb. 14.

    The breeding of clouded leopards has been a challenge, primarily due to male aggression, decreased mating activity between paired animals and high cub mortality.

    Little is known about clouded leopards. They are native to Southeast Asia and parts of China in a habitat that ranges from dense tropical evergreen forests to drier forest.

  • March — Capybara Babies

    David Barnhardt/Akron Zoo
    Image: Capybara babies

    These two furry critters are called capybaras. Capybaras (Hydrochaeris hydrochaeris) are the world's largest rodents, measuring about 3.5 to 4.5 feet long, and they live a semi-aquatic lifestyle in areas near lakes, rivers, swamps, ponds and marshes in much of South America.

    Mother capybara Courtney gave birth to five babies at the Akron zoo on March 24. Two of the babies died during birth and a third died after a surgery to repair its hip, which was dislocated during birth. Mortality of capybara babies is typically high.

  • April — Desert Bighorn Sheep

    Image: Desert bighorn sheep
    Tad Motoyama

    On Monday, April 26, 2010, a female desert bighorn sheep was born at the Los Angeles Zoo.

    Desert bighorn sheep are native to the high mountains and deserts of the south western United States and northern Mexico. Preferring to reside in places with rocky terrain and access to water, they completely avoid forested areas. In the wild, a herd is comprised of females and their lambs. When the males reach the age of two, they separate from the herd and set off by themselves in bachelor groups.

    As male desert bighorn sheep mature, they develop massive spiraled horns that may add up to one-third of their total body weight. Females have much smaller horns. However, both sexes have excellent vision and hearing as well as an innate ability for climbing rugged terrain.

  • May — Amur Tiger Cubs

    Image: Amur tiger cubs
    Julie Larsen Maher (c) WCS

    A trio of male Amur tiger cubs were born at the Bronx Zoo in May. The trio were the first Amur tiger cubs born at the zoo in more than a decade.

    Three Malayan tiger cubs were also born at the zoo this year. Amur and Malayan are two of the six surviving subspecies of tiger.

  • June — Kiwi Chick

    Image: Kiwi chick
    Smithsonian National Zoo

    The National Zoo held a naming contest for a Kiwi chick born on June 15. When the votes came in, the little bird was dubbed Areta (AH-reh-tah). The name is Māori — the language of New Zealand 's native people — and means "of noble kind."

    Areta is one of the first kiwis to be bred in captivity in the United States. Kiwis in captivity are very rare — only four zoos outside of New Zealand have been able to breed the birds.

    Kiwis (Apteryx mantelli) are small, flightless birds unique to New Zealand.

  • July — Black-footed Ferrets Kits

    Image: Black-footed ferrets
    Mehgan Murphy, Smithsonian's National Zoo

    Twelve litters of black-footed ferrets, a species once nearly extinct, were born at the Smithsonian National Zoo this year. The litter pictured here came into the world on July 23.

    In total, 50 kits, the term for baby ferrets, were born this year, and 49 have survived. The sizes of the litters this year were larger than those in previous years.

    Black-footed ferrets once lived in the short- and middle-grass prairies of the western Great Plains. Today, they are an endangered species as a result of disease and a 98 percent loss of the North American prairie ecosystem.

  • August — Komodo Dragon Hatchlings

    Image: Komodo dragon hatchlings
    Tad Motoyama/Los Angeles Zoo

    Starting on Aug. 8 and continuing for the next 11 days, 22 Komodo dragons hatched at the Los Angeles Zoo.

    On Jan. 22, 2010, Lima, the Zoo’s female Komodo dragon, laid 23 eggs. Less than 10 zoos in North America have been able to breed Komodos; these hatchings marked the L.A. Zoo’s first success at breeding them.

    Hatchlings are 14 to 20 inches long and weigh about 3 to 4 ounces. Komodos, the world’s largest lizard, can grow to approximately 9 feet, weighing up to 200 pounds or more.They are confined to a small set of islands in Indonesia.

  • September — Lion Cubs

    Image: Lion cubs
    Mehgan Murphy/Smithsonian's National Zoo

    A whole pride of lion cubs joined the Smithsonian National Zoo in August and September.

    On Aug. 31, lioness Shera gave birth to four cubs, three females and one male, which have now been named John, Fahari, Zuri and Lelie. Her sister Nababiep gave birth to three cubs, two males and one female, of her own on Sept. 22. They have been dubbed Baruti, Aslan and Lusaka.

    Lion Luke is the father to all seven cubs, which could make their debut in the lion's outdoor yard soon, weather permitting.

  • October — Baby Pied Tamarins

    Image: Baby pied tamarins
    Colm Farrington

    These baby pied tamarins were born at Durrell Wildlife Conservation Trust in the U.K. in mid-October.

    Sadly, one of their siblings did not survive, but the other two were reportedly doing well. A long hand-rearing process, during which the keepers fed the babies with formula milk every two hours around the clock, has insured that both tamarins are doing well.

    The pied tamarin (Saguinus bicolor) is a primate species found in a restricted area in the Brazilian Amazon Rainforest and is thought to be one of the most endangered monkeys in the Amazon.

  • November — Panda Cub

    Image: Panda cub
    Zoo Atlanta

    It may not look like it, but this teeny guy will one day grow into a Giant Panda. The cub, confirmed to be a boy, was the only Giant Panda cub born in the United States this year, making his a particularly notable birth.

    The boy, who will not be named until he is 100 days old, following Chinese custom, was born to Zoo Atlanta's 13-year-old panda Lun Lun on Nov. 3.

    Lun Lun and the cub will debut to the public sometime in spring 2011. Before then, catch mom and son on the zoo's PandaCam, Monday through Friday from 10 a.m. to 5 p.m. EDT.

  • December — Elephant Calf

    Image: Elephant calf
    Hannover Zoo

    On Dec. 9, this little elephant calf broke a world record — she was the fifth baby Asian elephant born at one zoo in a single year. The Hannover Zoo, where she was born, has a lot of baby elephants on their hands!

    The "little" girl, who will remain in doors due to the cold weather, weighs 290 pounds and was 39 inches in height.

    The other four baby elephants — Saphira, Nuka, Felix and Dinkar — were born on May 7 and 11, July 25 and August 6, 2010.


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