Punch the baby monkey has captured hearts worldwide for clinging to plush toy after his mother rejected him, reflecting a famous and cruel experiment on early attachment.

Born in July 2025, the baby macaque was abandoned by his mother and taken in by Ichikawa City Zoo in Japan.

Struggling to integrate with the rest of his troop due to his lower status in the hierarchy, he was seen often pushed to the ground by older monkeys.

To ease his anxiety and loneliness, zookeepers gave him a soft IKEA orangutan toy, which quickly became his constant companion, as baby macaques normally cling to their mothers for much of their first year of life.

Videos show Punch carrying his plush “mum” surrogate, hugging it, and seeking comfort after a scuffle with his group, and they have since gone viral.

Long queues have formed at his enclosure at Ichikawa City Zoo as visitors flock to see Punch, while the plush toy itself has sold out in stores worldwide. IKEA has even sent additional orangutan toys for him to enjoy.

But there’s more to Punch’s story than a viral moment.

Professor Mark Nielsen from the University of Queensland (UQ) said the tiny macaque’s attachment to his toy echoes a famous 1950s experiment by US psychologist Harry Harlow.

Harlow removed rhesus monkeys from their mothers and gave them two surrogate “mothers”: one made of wire that provided food and drink from a small feeder, and one covered in soft terry towelling.

“This doll was soft and comfortable, but it didn’t provide food or drink; it was little more than a furry figure the baby monkey could cling to,” Nielson explained.

“So, we have one option that provides comfort, but no food or drink, and one that’s cold, hard and wiry but which provides dietary sustenance.”

The experiment challenged the behaviourist view at the time, which suggested primates, including humans, form attachments based on reward and punishment and follow whoever meets their physical needs.

Therefore, researchers expected the monkeys to stay with the wire “mother” that provided food.

But that didn’t happen: the baby primates spent most of their time clinging to the soft, towel-covered “mother,” showing that comfort and emotional care were far more important than just being fed.

“Today, we would see Harlow’s experiments as a cruel and unkind thing to do,” Nielsen said.

“You wouldn’t take a human baby away from its mother and do this experiment, so we shouldn’t do this to primates.

The zoo wasn’t running an experiment, but Punch’s situation unintentionally mirrors Harlow’s study.

The setup happened naturally, yet the outcome is strikingly similar.

“It’s interesting to see people so fascinated by this parallel to an experiment conducted more than 70 years ago,” Nielson said.

“Punch is not just the internet’s latest animal celebrity; he’s a reminder of the importance of emotional nourishment.

“We all need soft spaces. We all need safe spaces. Love and warmth are far more important for our wellbeing and functioning than physical nourishment alone,” Nielsen said.

The experiment helped shape modern attachment theory, which holds healthy development depends on children forming secure emotional bonds with attentive caregivers.

Without warmth and emotional support, even a well-fed child may fail to form a secure attachment.

Punch’s plushie may not provide food, but it gives him exactly what he needed, a safe and comforting presence after being rejected by his mother.

Since forming his heartbreaking bond with the plush “mum” surrogate, Punch has begun making friends with other macaques in his enclosure, slowly moving up the social ladder while keeping his beloved toy close.