When most people think of sharks, they think of species like the great white shark, tiger shark, and bull shark. These are known as requiem sharks and have that classic shark appearance. However, there a numerous species of shark that look very different from requiem sharks including the nurse shark (Ginglymostoma cirratum). These are very common sharks in the Caribbean and often encountered by new divers.
The head is broad with tiny eyes and has two barbels (whisker-like appendages) that are used in the search of food. Their teeth are small and designed for crushing as part of their diet includes eating shrimp, crab, and lobster. They are nocturnal and during the day they are often seen laying under ledges but are also seen in the open on the sand.
They are a fairly large shark and can reach over 3 meters or about 10 feet although most are much smaller. They can tip the scales between 90 to 115 kg (200-250 pounds). The gestation period for nurse sharks is about 6 months and generally, they have between 20-30 pups.
Although many divers see them as harmless, their mouth can produce a tremendous suction and could easily suck in fingers or a hand which they generally will not let go of. Therefore, like all sharks, they must never be touched and need to be respected.
We arrived at this dry riverbed at just the right time to see this small herd of elephants. The rains were late and had not arrived in the Serengeti yet. After a few minutes, it became apparent why they were here. In the photo below you will notice a small hole in the sand about the width of their foot. Inside there is water.
We assume that the elephants have dug this hole themselves into the dry riverbed. The Serengeti can be a tough place to live in and animals must be innovative to survive. The adults will pass these skills onto the young calves.
Elephants have a wonderful group dynamic. They work collectively for the survival of the herd. As large as they are they are amazing coordinated and use their feet and trunks to perform tasks that you would think they would be incapable of. However, if you are a young calf, drinking all that water can be exhausting and sometimes you just need to get off your feet.
Fortunately, we were able to spend about 20 minutes with this herd before they had all drank from the water hole and began moving on. This group of seven consisted of 2 calves, juveniles (male and female) and adults. We never get tired of seeing and photographing elephants.
Although we love to photograph all sharks, our favorite is the great hammerhead (Sphyrna mokarran). Generally, it is a cautious shark and will keep its distance from scuba divers. There are 9 species of hammerhead sharks worldwide but the great hammerhead is the largest. An average adult reaches lengths of about 3.6 to 4.3 meters (12-14 feet) but can reach 6 meters (20 feet) and exceed 550kg (1,200 pounds).
Great hammerheads are newer sharks on the evolutionary scale and have developed some unusual characteristics. The unique feature of this shark is obviously the head. The “hammer” which is called a cephalofoil is full of electrical sensors. These pores called ampullae of Lorenzini aid in hunting as these sensors pick up electrical signals given off by all living creatures including humans.
As you view these photographs notice how different the shark can look depending on the angle of the photograph. On a larger shark, the cephalofoil is about a meter (3 feet) in length and the eyes are at the ends which gives it a large range of vision.
The diet of this shark is diverse. They will feed on a variety of fishes including tarpons, porcupine fish and even other sharks. As well, lobster, squid, and octopus form part of their diet. However, their favorite food is rays. Stingrays bury themselves in the sand and the great hammerhead uses its cephalofoil with its electrical sensors to detect their location.
Two different encounters with humpback whales (Megaptera novaeangliae) during our Mexican holiday make up this post. The first experience was breaching humpbacks while in Cabo San Lucas (Baja California Sur) on the Pacific Ocean side. We followed three whales for about an hour and only had them break the surface to breathe. Shortly after this, they got more active and for about 5 minutes and they breached a number of times.
We have over 500 dives and have never encountered humpback whales underwater. In Hawaii, we have heard the males singing during our dives but they always seem to avoid us. All that changed in the Socorro islands (Revillagigedo Archipelago). We had a very brief encounter (about 10 -15 seconds) with a mother and her calf. They were moving toward us but immediately turned away to avoid us, but this allowed for a couple of quick photographs. This was a very surreal experience to see a 13-15 meter (40-50 foot) whale and calf such a short distance from us!
Our previous posts on the Revillagigedo Archipelago, also called the Socorro islands, have included the giant mantas(Manta birostris), whitetip reef sharks(Triaenodon obesus), and silky sharks (Carcharhinus falciformis). Although Galapagos sharks (Carcharhinus galapagensis) are fairly common especially at Roca Partida, we did not have any encounters with them there. However, on one dive we did come across a few juveniles at Socorro island and this gave us an opportunity to photograph this species.
Older sharks of all species have very scarred bodies which are simply a result of surviving in a dangerous ocean environment. However, these juvenile Galapagos sharks, which were about a meter (2-3 feet) in length, had skin with very few blemishes. Adult Galapagos sharks can reach 3 meters (9-10 feet) in length.
The silky shark (Carcharhinus falciformis) gets its name from the smooth texture and silky look of its skin especially when it is young. These sharks can grow to 2.5 meters (8 feet) in length and are very abundant in the Revillagigedo Archipelago. Generally referred to as the Socorro Islands, these volcanic islands lie approximately 390 kilometers (240 miles) off the coast of Cabo San Lucas in Mexico.
Although we encountered scalloped hammerheads, tigers, Galapagos, whitetip reef, and silvertip sharks the most numerous were the silky sharks. At dusk, as the sun was setting, a few of us slipped into the water behind the boat in an attempt to photograph these sharks with the sun’s rays penetrating behind them to give a visually stunning look. Thank you to Andy Murch of Big Fish Expeditions for showing us this technique as we are relatively new to underwater photography.
The focus of our trip was to photograph the giant mantas (Manta birostris) at San Benedicto Island in the Revillagigedo Archipelago. These are the largest mantas in the world and can be more than 20 feet (6 meters) across and weigh up to 3,500 pounds (1600 kilograms). The dive site called “the Boiler” is a cleaning station for these mantas where fish remove parasites from their bodies. Consequently, this site provides the best opportunities to see and photograph these gentle giants.
The Revillagigedo Archipelago lies approximately 390 kilometers (240 miles) off the coast of Cabo San Lucas in Mexico. These Pacific islands are more commonly referred to as the Socorro Islands. Aboard the Southern Sport, we dove 3 of the 4 islands (Roca Partida, San Benedicto, and Socorro).
A color variant from the more common black and white manta is an all black or nearly all black manta. It is not a different species of Manta birostris. However, it is exciting when one showed up as it looks so different.
San Benedicto is the island for the giant mantas. They are used to divers and show no fear of people. They swim It seems a bit surreal, even a few weeks after our encounter with them, to have had huge mantas swim within a few meters of us.