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North American River Otter Litter Born
at the Milwaukee County Zoo

Otter pups

Posted May 2022

The Milwaukee County Zoo’s first surviving litter of North American river otters made their debut to visitors May 17 in the outdoor Otter Passage habitat!  The three male and one female pup were born February 7 to mom, Shamrock, and dad, Malarkey (Larkey).

Otter pupsThe new arrivals marked their 3-month birthday May 7, and zookeepers report all are doing well, spending their first few months in the behind-the-scenes holding areas of the habitat.  Shortly after birth, the pups nursed from mom, slept many hours of the day, usually nestled together.  The pups can now swim on their own (usually in a group) and navigate the outdoor habitat, while Shamrock continues to keep a watchful eye on them.

Otter pupsKeepers also report that for now, the otters seem to prefer the shallow of pool in their habitat, and in time, think they’ll begin to venture into the deeper pool. For now, they swim in a group with Shamrock, and don’t seem to mind visitors watching them. Keepers have seen the pups putting their feet onto the habitat glass!

Average weight for the pups is between 6-7 pounds, and they’re no longer nursing from mom.  Their diet consists of five different types of fish, and dry pellet food for extra vitamins and nutrients.

Posted March 2022:

The zookeepers from Small Mammals, who are carefully tending to the pups since birth, have given them names! In keeping with the Irish theme (Mom Shamrock was born on St. Patrick’s Day in 2017) the names are:  Evie for the girl, Cedrick, Corky and Bailey for the boys.

The Milwaukee County Zoo is excited to announce the birth of four North American river otter pups born February 7! Three male and one female pup were born to mom, Shamrock, and dad, Malarkey (Larkey). This is the first surviving litter for the pair.

So far, Shamrock is displaying excellent maternal care toward the pups. Animal care staff comment that she’s extremely attentive and stays with the pups nearly every hour of the day, in an off-exhibit holding area. She cleans and grooms the pups and has even been seen bringing her food into the area to be close to them.

Otter pups
The four pups snuggle together.

While the Zoo’s other female, Clover, and male, Larkey, remain in the outdoor habitat, Shamrock and the pups are living together (the pups are usually curled up in a ball next to each other), in the indoor maternity den, with soft, natural bedding material for warmth and comfort. The den consists of several separate habitat areas, or compartments, for Shamrock to easily move the pups from one area to the another if she decides.

One of the compartments has a nest box, and the entire den, or suite, is quiet, with additional heat and humidity to keep the pups comfortable in their first weeks of life.

Otter pup
At 1 week old, animal care staff check the teeth of an otter pup.

Because this marks the first successful litter, zookeepers are careful to keep a consistent daily routine for Shamrock, so there is no distress during her days and nights. The pups are weighed daily, always at the same time. At birth the pups weighed ~125 grams each, and have continued to gain weight every day since. Keepers closely monitor mom and the pups and report they appear to be healthy and developing well.

Shamrock is nursing the pups, who should be fully weaned at 3-4 months. In 42-56 days, they’ll begin eating fish that the keepers will “mash” for them, or fish that Shamrock drops from her mouth! North American river otter pups are born with their eyes closed, and they’ll remain closed until about 1 month old.

Otter pup
One of the pups at 2 weeks old.

As the pups continue to grow and mature, keepers are noticing some “squirming” and “belly crawling” in the holding areas. At times, Shamrock may leave the pups for a very short period during the day for a quick swim in the indoor holding pool, but she immediately returns to them afterward. She takes her swim only after nursing the pups.

Keepers say they usually see the pups nestle together and sleep many hours of the day. It’s expected the pups will learn how to swim from mom, at about 1 ½ months old. They will walk first, and then learn how to swim in the indoor pool.

The new arrivals marked their 1-month birthday March 7, and Shamrock and the pups, who have yet to be named, will remain off-exhibit for the next few months. Animal care staff are keeping a watchful eye on them, and the Zoo will regularly update visitors on their progress.

Video: Otter pups make their debut in the outdoor habitat, Otter Passage