IDAHO FALLS — A fan favorite red panda at the Idaho Falls Zoo died unexpectedly at 2 years old.

The zoo announced in a Facebook post Wednesday that Marvin, a red panda born at the zoo, died for reasons not yet known. He was the first red panda born at the zoo and was cared for in accordance of the Association of Zoo’s and Aquariums red panda Species Survival Plan.

“Instantly a fan favorite we all became invested in the journey of this special little guy,” the zoo wrote in the post.

As part of the Species Survival Plan, Marvin was moved to Zoo Knoxville in Tennessee to be cared for by red panda experts after Marvin’s mother neglected to care for him. There he met another red panda who would become his mate, Linda, and the two of them were brought to the Idaho Falls Zoo early in 2021.

Marvin and Linda had two cubs, Saffron and Paprika, who were born on July 1 at the zoo.

Red pandas have been on the International Union for Conservation Nature’s endangered list since 2008. The red panda population has declined by more than 50 percent over the last 20 years and scientists estimate there may be 2,500 red pandas remaining in the wild today, according to the Smithsonian’s National Zoo and Conservation Biology Institute.

Zoo staff conducted a necropsy and found no obvious indicators of Marvin’s death, the zoo wrote in the post. Tissue samples were collected and sent off for further study. The zoo will inform the public of its findings after more information becomes available.

Marvin’s death was early compared to the average lifespan of his species. Red pandas may live as long as 23 years and show symptoms of age at around 12 to 14 years old, according to the Smithsonian.

“We are all feeling the loss of Marvin, a beloved friend of the community and, let’s be honest, a staff favorite. We sure hope you all enjoyed getting to know him as much as we have. While we take this time to mourn his loss we are also grateful for the time he spent with us and his contribution to the species survival as a whole,” the zoo wrote in the post.