If you are looking for proof that primates are the closest animal relatives to humans, this video uploaded by TikTok user @ihsahnmohd might do the trick.

When visiting the Singapore Zoo with his expectant wife, an orangutan leaned against the exhibit's glass panel as if it was trying to listen to the foetus' heartbeat, just like a close relative would.

Human-animal interaction

The heartwarming interaction was captured in a 33-second video clip that was posted to TikTok on July 8.

The clip has since garnered 17,100 views and 1,343 likes.

In it, Ihsahn's wife can be seen pressing her baby bump against a glass panel.

On the other side, an orangutan squishes its right ear and cheek against the panel, near where her baby bump is.

Ihsahn writes in the on-screen captions that the "orangutan came to my pregnant wife and listen [sic] to the baby's heartbeat".

At one point, Ihsahn's wife leans forward to take a closer look at the orangutan's face.

The ape then turns his head to gaze curiously at the lady's baby bump, before pressing his ear and cheek against the glass again.

Clearly, that the human and ape were separated by glass did not diminish the sense of connection between the two.

@ihsahnmohd Orang utan listening to baby in tummy@Singapore Zoo #singapore #singaporezoo #singaporetiktok #orangutan #wholesome #fyp ♬ Home (Option 3 - The Young Ebenezers

In the comments, Ihsahn shared in his response to a comment that it "was a really good experience".

One commenter noted that the name of the orangutan is Charlie, and that he was comfortable with humans as he had been "hand raised from young".

Another commenter pointed out this behaviour was not a first for Charlie, as he had done the same thing with their mother.

46-year-old Charlie often spends time people-watching

Charlie is a 46-year-old male Sumatran orangutan born on Dec. 1, 1977, in Zoo Negara located in Selangor, Malaysia.

Orangutans have a lifespan of 35 to 40 years in the wild, and up to 60 years under human care.

Charlie arrived in Singapore on Jun. 8, 2005, as part of an exchange programme with Zoo Negara.

The exchange is meant to ensure a sustainable population of orangutans under human care.

As of Jul. 14, 2023, Charlie weighs 96kg.

The male ape is known to like the attention of humans, owing to his being hand-raised since young.

Charlie's favourite pastime includes people-watching, and is most intrigued by women and children.

He can be regularly seen in front of his glass-fronted exhibit to observe visitors.

As for the affectionate behaviour observed in the TikTok clip,  Charlie, and orangutans in general, are not the only ones known to display such behaviours.

"This curious behaviour is not unique to Charlie as there have been many instances of great apes showing interest and being sensitive towards not only expectant ladies, but infants and children as well," a Mandai Wildlife Group spokesperson told Mothership.

Sumatran orangutans are classified as "critically endangered" on the International Union for Conservation of Nature Red List.

Top image via @ihsahnmohd/TikTok