Pinkness is a layered effect
A boto’s color is not simply a coat of pink pigment. As the dolphin’s gray coloration becomes less prominent, the skin’s underlying rosy tone becomes easier to see. Repeated abrasions add another layer to the effect: when skin heals, scarred areas can remain pink, making an older dolphin look mottled rather than uniformly colored.
That is why two adult river dolphins can look quite different. One may be mostly pink, another gray with scattered pink patches. Age helps explain the change, but it does not set a single timetable or final shade.
A record written on the skin
The marks are connected to the animals’ lives. Botos move through a river habitat crowded with submerged branches and other obstacles, and they interact physically with one another. Scrapes that heal leave visible traces, so an animal’s skin can accumulate a history of wear as it grows older.
The pink appearance is therefore both a matter of changing coloration and of what happens to the skin over time. A gray juvenile may gradually develop a more pink-looking surface, while an adult’s scars make that color uneven. The result is not a simple age label: pinkness offers a clue to an animal’s changing skin, but it cannot tell its exact age.
