WASHINGTON – Loki, the black howler monkey born earlier this year at the National Zoo, was euthanized Sunday, the zoo says.

Less than 7 months old, Loki became ill from a metabolic bone disease, which is an imbalance of phosphorus, calcium and vitamin D and is most often caused by lack of sunlight, lack of dietary intake of vitamin D and the body’s inability to properly metabolize these compounds, reports the zoo.

Loki was treated in the hospital for five days, but the monkey continued to grow weaker.

Loki’s death comes just weeks after the Zoo lost its much anticipated giant panda cub.

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