After spending her first three months in the Cub Den at the Point Defiance Zoo in Tacoma, Wash., Sumatran tiger cub Kali got her first chance to play outside in July. The hand-reared cub will be 4 months old this Saturday, and we’re celebrating with a look at some photos of the 30-pound baby exploring — and sleeping.

This beauty was born on April 17 to 9-year-old mom Jaya and dad Malosi. Kali’s keepers quickly stepped in to hand raise her after Jaya showed little interest in her then 2.5-pound cub. Kali recently moved from the zoo’s Cub Den, where she roomed with a clouded leopard cub, to the Asian Forest Sanctuary.

The feisty cub wasn’t shy about checking out her yard for the first time last month. “She’s spunky, robust and energetic,” zoo staff biologist Steven Ok said when Kali was just 3 weeks old.

The pouncing cub has two big brothers at the zoo: 1-year-old Dumai, who shares the same parents and was also hand raised because Jaya wasn’t interested in caring for him; and Berani, a Malayan tiger cub who was born within days of Dumai at the Tulsa Zoo and was transferred to Point Defiance last October. (See the boys’ antics in this video.)

Little Kali sprawls out in the grass. Sumatran tigers are critically endangered, with only 74 living in North American zoos and 300 on their native Indonesian island. “Female cubs are particularly needed in this population,” said Karen Goodrowe Beck, the zoo’s general curator. “She is a welcome addition.”

All that playing is exhausting for a kitten like Kali. It’s time to rest those piercing green eyes! If you missed it, it’s worth watching this video of the cub napping at about 1 month old.