Dolphins can develop diabetes if they lack sufficient pentadecanoic and heptadecanoic acids in their diet, which can be cured by adding these acids back.

“if you're a dolphin who never eats carbohydrates in your entire life and you have not enough pentadecanolic and heptadecanoic acids in your diet you get diabetes well why on earth would a dolphin ever get diabetes it just doesn't make any sense but if you add it back in you cure them”