Research partners spotted two endangered main Hawaiian Islands insular false killer whale calves this year, and they’re starting to grow up! This is a rare and exciting discovery for this small, resident population of only about 140 individuals.
NOAA staff with the Hawaiian Islands Humpback National Marine Sanctuary first photographed the newborns off Maui in February. In August, Captain Zodiac staff spotted them again and alerted Cascadia Research Collective, a NOAA collaborator.
The first 6 months are an especially vulnerable time for calves, so seeing them swimming strong at roughly 8 months is encouraging.
This is big news for the only endangered population of false killer whales in the world!
Newborn Calf Sightings Are Rare
Only 10 newborn calves have been documented in this population since 1999. That makes this discovery extra special.
NOAA Fisheries works with partners to recover the endangered population. With roughly 140 individuals remaining, recovery is a slow process—and not just because of the small population size.
Rebuilding their numbers is also slow because of false killer whale biology. Females take nearly a decade to reach calf-bearing years.
We’re still working to determine the actual reproductive rate for the endangered population, but data indicates females typically give birth only once every 7 to 9 years. Over a lifetime, that translates to about 4 to 7 potential calves per female.
False Killer Whales Stick Together
False killer whales are highly social animals that stick together. The main Hawaiian Islands resident population is especially close knit. In fact, they’re genetically distinct from other false killer whales.
We refer to them as a resident population because they live within about 50 miles of the main Hawaiian Islands—a distance roughly the length of Oʻahu.
Their small population is divided into four social groups, called clusters. The two new calves are part of Cluster 1. Research has shown that individuals in the main Hawaiian Islands resident population will live and hunt within their cluster for most of their lives.
First Known Calf for Mother HIPc0363
Our partners at Cascadia Research Collective have been tracking mother HIPc0363 since she was first spotted as a juvenile in 2009. This is the first year they’ve seen her with a calf, and we believe it’s her first.
Female false killer whales mature slowly. They reach reproductive age around 8 to 11 years old, and when pregnant, they carry their calves for about 14 months. After birth, they nurse their calves for up to 2 years. These long-term investments in raising young mean that mothers usually only give birth once every 7 to 9 years.
These moms have something unique in common with human females—they experience menopause. False killer whale females typically stop reproducing in their early 40s, but can live into their 60s. Scientists aren’t sure why. One theory is these older females fill a social group need by assisting with child-rearing activities like food sharing, protection, or skill development.
With few reproductive females producing calves so infrequently, every calf that survives is important for the population.
How You Can Help
The main Hawaiian Islands insular false killer whales may keep their young in nearshore waters. If you encounter these endangered resident whales, please give them space to allow them to nurse, socialize, and rest without disturbance.
Here are other ways you can make a difference:
- Report all sightings to the NOAA Marine Wildlife Hotline: (888) 256-9840
- Keep trash and harmful chemicals out of storm drains and the ocean
- Fish responsibly—immediately report accidental hookings and lost catch, use barbless circle hooks, and fish elsewhere if you spot false killer whales
