Two amiable red panda cubs living at Lincoln Park Zoo in Chicago are now one step closer to leaving their dens and greeting the zoo's visitors.

Born on June 26, Clark (male) and Addison (female) were featured on Zooborn in August. The furry pair is healthy and very curious of their surroundings.

The adorable pair recently underwent their second physical exam. Clark's weight had doubled and Addison's weight had tripled since their initial exam on July 10, surpassing milestones such as nursing and opening their eyes, WGNTV reported. The cubs have also begun changing from their pale yellow fur into the auburn coloration commonly seen on Red Pandas.

"The cubs are often seen trying to explore outside of the den before quickly being scooped up by their mother Leafa," said Curator of Mammals Mark Kamhout.

The Red Panda cubs received their check-up from keeper and veterinary staff, including Dr. Kristina Delaski, who is the veterinary advisor for the Red Panda Species Survival Plan (SSP), which manages the accredited zoo population.

Keepers and veterinarians are still closely monitoring Leafa and her cubs, which currently remain off-exhibit. Phoenix, the pandas' father, is on exhibit daily at Lincoln Park's Kovler Lion House from 10 a.m. - 5 p.m.

Much smaller than black-and-white Pandas, Red Pandas are small arboreal mammals residing in the mountains of Nepal and northern Myanmar, as well as in Central China.

Also known as Red Bear-Cat, the animal is classified as vulnerable by the International Union for Conservation of Nature (IUCN). The Red Panda wild population is approximately less than 10,000 mature individuals.

Spending most of its time on trees, the Red Bear-Cat is slightly larger than a domestic cat. It has reddish-brown fur, a long, shaggy tail, and a waddling gait due to its shorter front legs. It feeds mainly on bamboos, but it also eats eggs, birds, insects, and small mammals.

Just like other solitary animals, red pandas spend the majority of their lives alone, except when mating or raising their young. They are active from dusk to dawn and are largely sedentary during the day, National Geographic reported.