Continued from yesterday”¦ Sperm whales dive the longest and deepest of all the whale species, going down between 1 3 km deep and staying down about an hour. The longest recorded dive is 2 hours and 40 minutes. They will come back up for about 20 minutes to re-oxygenate their blood, then dive back down to continue hunting. There is no light that deep, so have an amazing sonar system to find food. They primarily eat squid, and have the most powerful sonar system of any animal. Males can reach up to 60 feet and 125,000 lbs. (18m and 60 m tones). Females are ½ the length and 1/3 of the weight of males. Babies are about 13 feet and 2200 lbs (4m and 1 m tonne) at birth. Sperm whales live between 50 and 70 years and can be found just about everywhere in the world with waters deeper than 3,000 feet (1,000m).
Female sperm whales travel in groups, along with their calves, and live in tropical or sub-tropical waters all year. A female sperm whale starts breeding at about 12 and continues to breed into her 40’s. She has an 18 month gestation period. When her calf is around two years old, she will breed again, so each female has about one baby every 4 years or so, delivering about 10 calves in her lifetime. The babies can’t stay underwater for very long, so one female at a time will stay on the surface with the baby as the others hunt for food. When the whales sleep on the surface, they make a ring with their heads in the center and their tail fins out. They put baby in middle, and thus are able to shoo off any potential predators with their fins.
The male whales migrate away when they are between 6 and 9 years old. They are not exactly sure where the males go, but it is almost certainly to colder waters up north, and possibly even the Arctic Circle. After being gone for 15 years, the males come back to tropical waters to mate. They meet up with a female for a season, then move on again. Part of his research is on the whale cultural groups. Whales have distinctive cultural groups with learned behavior patterns and dialects, just like humans. And, like humans, they communicate primarily via sounds. The whales instinctively know not to mate with someone who speaks their own dialect. It is nature’s way of preventing inbreeding.
And why are they called sperm whales? The whales have a special oil that that amplifies their sonar. In old times, it believed this oil was sperm, hence name. It is believed that there used to be 1.6 million sperm whales in days of old, and today there are only about 300,000. In the Pacific, there is a serious shortage of males, so often females can’t find a male to mate with when they are ready.
While the guide was giving us all this information, the rest of the crew was diligently searching for whales. They would drive out a few miles, then stop and listen for the whales using a hydrophone. A hydrophone is basically put a waterproof microphone in a padded pot, and attached the pot to a long pole. The pot limits the sound so they can only hear from one direction at a time. They stuck the pole in the water to get the pot nice and deep, and listened through headphones for the sonar sounds. Since the whale’s sonar is so strong, it is also loud and can be heard from miles away. They can hear dolphins, too. If they hear the sonar sounds, they head off in that direction.
Unfortunately, they weren’t hearing anything at all, so they continued to move the boat south and west, away from the island and into the channel, still stopping every few miles to listen. Our guide explained that the whales don’t care for the run off from the rain water, and stay farther away from the island when it has been raining a lot. As we got farther away from the protection of the island, the ride got wetter and rougher. We are so glad we have an enclosed pilot house. We can’t imagine having to sit outside for hours on end with waves hitting you. And we don’t think the motion is better on a cat than a monohull, just different. Eric actually prefers the monohull motion, as he doesn’t like lurchy.
Near the channel, the person handling the microphone finally heard the whales farther ahead in the channel. We followed the sounds. The four crew scanned and scanned and scanned the horizon, but nothing. It was getting late, and it was time to head back. We were bummed that we were part of the 10% that doesn’t get to see them. Just as they were about to give up, one of them spotted a whale in the distance. The spotters have amazing eyes. The whales were barely visible, so difficult to discern that we can’t believe they actually saw it. We watched it for a few minutes before it dove deep. It didn’t do any exciting tricks for us, in fact, we barely saw the animal itself, mostly just the mist from the blowhole.
The guide explained that since they take turns going down, another one would be on the surface soon. We waited and scanned the horizon. But was getting dark and we needed to get going. We were bummed that our one and only sighting wasn’t very dramatic or spectacular, but at least we got to see one whale and we learned a lot from the PhD student.
As we were going back, one of the crew spotted another whale and we stopped to watch. This time it was a mama and baby nursing. The light was waning and we could barely see them. Honestly, if the guide hadn’t explained the nursing, we wouldn’t have realized there was two of them. He would say “Ok the mom is on top now”¦OK, in just a second the mom will exhale then roll over and the baby will be on top”, then, just as he predicted, a spout of water out of the blow hole and the two would turn. He told us exactly when the little flukes were coming from mama and baby, and when the big, dramatic fluke came from mama indicating that mama had just dove deep. It was awesome. Awesome to see something so special as a nursing mother and child, and awesome to have it explained so well. It really made the trip worthwhile and special. In between rolls, the guide told us that the sperm whales are the only ones to nurse on the surface, and one of the things they are actively studying is their unusual nursing practices. From what they can tell, it looks like the baby nurses through its blowhole, not its mouth.
When we finally got back to shore it was 1830. We were worried we may have missed the last bus back to Portsmouth. The reception desk confirmed the last bus would be leaving the bus station soon, and that we’d likely have a hard time finding a local bus to take us to the bus station at the north end of town at this hour. Fortunately, a couple fellow compadres from the whale watching cruise had a car and kindly dropped us at the bus station at the far end of town. And we made it on the last bus.
On the bus ride back, we had a lively conversation with a couple of the locals, which was fun. We always love talking to the locals and hearing what they have to say about their country, lives, culture, politics, and so forth.
When we got back to Portsmouth, we found a restaurant to have dinner at before heading back to Kosmos. Eric ordered jerk chicken. It was very spicy, a little too spicy for him, and not as tender as he hoped for. He found it to be kind of tough & crunchy. Christi got Dominica style chicken, which was tender and yummy (pictured below). The sauce had a sweet base with a variety of seasonings thrown in. It had a little bit of a kick, but nothing too strong. It was served with several side dishes. The first was a spicy baked pumpkin dish that didn’t taste like pumpkin at all. It is different and we are not sure that we liked it. The meals also came with pan fried sweet potatoes, salad, mixed veggies, rice and beans. All the rest of the sides were tasty.