Ontogeny (also ontogenesis or morphogenesis) describes the origin and the development of an organism from the fertilized egg to its mature form. 

The bottlenose dolphin life cycle:

Bottlenose dolphin females ready to mate at age 4 and their gestation period is 12 months.


Is Sponge Use Genetic?

Upon analysis of the mitochondrial DNA of 13 sponge using individuals and 172 non sponge using individuals, it has been found that the use of sponges in foraging is a trait that is passed on mostly within a single family line and is a recent trait. There is no to suggest that the sponge use is matrilineal among the female mitochondrial DNA line. 

Further analysis states that sponge use is not a sex linked trait, either. Behavioral observations have revealed that only females of the species utilize sponges in hunting. If the trait were sex-linked to the Y chromosome, only males would exhibit this behavior, and if it were linked to the X chromosome, then both males and females would have a chance at receiving this trait. This suggests that it is a learned trait. 

More evidence against a genetic trait for sponge use comes from the social interactions of dolphins; males do not spend time with the females
during their growth and development, but instead separate early on from their mothers and engage in playing
and hunting with other male dolphins. The females of the species, however, stay with their mothers for the first
four years of their lives.  These observations provide strength to the evidence for culture in marine mammals.