19.11.2025 – Mama time

Like all mammals, cetaceans give live birth to their young and care for them until the little ones attain their own independence. How this happens, from pregnancy up to the independence of the calves, largely depends on the species.

This morning we met two of Madeira-s most important predators; the Short finned pilot whale (Globicephala macrorhynchus) and the Bottlenose dolphin (Tursiops truncatus). The animals were observed in close proximity to one another and it isn’t a rarity to even see them interacting. Often, we see groups containing young animals from both species swimming together, a sighting that leaves us wondering whether the mothers use such interactions to introduce their young to other oceanic inhabitants.

These interactions occur despite major differences in how and how long mother and offspring interact. Bottlenose dolphins have gestation periods that last a year and an extended nursing period that can last up to 2 years. After weaning the young still are dependent on their mothers and generally stay at their side for an average time frame of 3-5 years. Once a Bottlenose dolphin is fully independent, it may choose to stay in its mothers pod for some time but may also leave right away.

Pilot whales do things differently. Their gestation period is much longer; 15 months, the age my son was until today. Their weaning period is lengthy and varies, lasting between 18 and 44 months! The long nursing periods help cement the bonds between the calf and several females in the group that also nurse the family’s offspring. Calves stay with the family pod for some time, females will in fact remain with their family forever.

In the afternoon both these species were encountered again, along with another incredible dolphin species: False orcas (Pseudorca crassidens)! These larger dolphins share their gestation period with their fellow “blackfish” the pilot whales and average 14 to 15 months. The calves are nursed for up to two years but will remain near their mother and in the pod for several more years.

So while two of the mentioned species share the same distribution, their gestation periods, social lives and weaning periods vary significantly, an ode to the incredible diversity amongst dolphins.

By Paula Thake

Sightings of the day

Ribeira Brava

14:00 Bottlenose dolphins, Short-finned pilot whales

Stenella

09:30 Bottlenose dolphins, Short-finned pilot whales

13:30 Bottlenose dolphins, False orcas, Short-finned pilot whales