WASHINGTON — Giant pandas Bao Li and Qing Bao are showing early signs of a future bond at the Smithsonian’s National Zoo, where the juvenile pair has grown increasingly interested in one another at the “howdy” window that separates their enclosures.

Though both are still too young to breed—just 3.5 years old—their recent behavior has mirrored hormonal changes often seen in adult pandas preparing for mating. Qing Bao recently experienced her first estrus cycle, confirmed through routine hormone testing conducted by zoo endocrinologists.

The pandas, who arrived last fall, have been observed vocalizing, scent marking, and spending more time near one another, much to the delight of animal care staff.

While breeding is still years away, officials say the growing connection between Bao Li and Qing Bao is a promising sign for the future of the species, which remains endangered in the wild.

Source: Smithsonian National Zoological Park