It didn’t measure its size, only its need to feel safe.
The video shows a young kangaroo, already grown, pushing its head against its mother’s pouch in a desperate attempt to get back inside. The pouch, that refuge that sheltered it from when it was a newborn joey through its first months of life, no longer has room for it. But instinct doesn’t understand measurements: when it feels afraid or seeks protection, a young kangaroo may try to return to the only place where it was always safe.
The mother, patient, lets it try even though she knows it no longer fits. It’s that same scene you may recognize too: wanting to go back, even if only for a second, to the place where everything was simpler.