Walking Back Through Time: The Ancient Fishes Exhibit

Since so much of life on Earth emerged and diversified in the ocean, walking around the Aquarium can be a bit like walking back through time. This is especially true in the Ancient Fishes exhibit in the Aquarium’s Thinking Gallery.

Many of the ancestral forms of these fishes first appeared hundreds of millions of years ago. That makes these fish older than the oldest dinosaurs! At that time, much of North America was a large equatorial swamp. As the water temperatures rose, oxygen levels dropped. As a result, some of these fish developed new ways of getting essential oxygen from the air.

Let’s take a closer look at one of our ancient fishes:

(Australian lungfish photo by Tannin)

Is that a giant salamander? Actually it’s a Australian lungfish. Though this Australian lungfish has a single lung, it mostly uses its gills to breathe.

The African lungfish, however, has two lungs and can actually drown if held underwater. During the dry season, this species can burrow into mud and spend several years in a dormant state called estivation. [Note: In 2009, Aquarium trainers worked on training an African lungfish to swim through a tube to get food. Photos and video from those efforts are in this post, scroll down.]

(African lungfish photo by Jeremy Brodt)

Looking at these animals, with their air-breathing habits and paired limbs, it isn’t too hard to imagine that amphibians like this axolotl below evolved from fishes such as these.

(axolotl photo by Stan Shebs)

In fact, all vertebrates—including reptiles, birds and mammals—evolved from ancestral, air-breathing fishes.

And just to set the record straight, just because a fish species is considered "ancient" does not mean that it is primitive. So-called "ancient" fishes are themselves the result of hundreds of millions of years of evolution, and are very well-adapted to the habitats in which they live.



What's Up, Dock?

A lot of fun outdoor programs start up at the Aquarium during the summer. One is the Dock Program, which aims to connect visitors to the ocean habitat right outside the Aquarium's doors. Boston Harbor is a beautiful and fascinating environment, with lots of animal life living just out of view. But not everyone even knows the Harbor is a harbor and not a river. So, to help our visitors get to know the harbor, we have placed a crab trap and other pieces of equipment into the harbor just off of our dock.

From left: Teen interns Alex Rojas, Kenneil Toney and Adora Thompson set up for the dock program

Throughout the week (especially on Thursdays, Fridays and Saturdays) we pull these up to see what kind of animal life we find. But we don't just look at the animals; we try to learn something about them as well. Our teen interns (and visitors who want to participate) take observations on the time of day, the weather conditions, the tidal heights and the turbidity of the water (or the water transparency) to learn more about the conditions under which our animals live. This also serves as an introduction to basic marine science.

In the photos below, you can see our teen interns setting up for the Dock Program and gathering data, and you can see a couple of the animals they found during that day's program.

Teen intern Adora Thompson takes a secchi disk measurement. By lowering the secchi disk into the water and measuring the depth at which the white part of the disk is no longer visible, you can learn some basic information about the turbidity (cloudiness) of the water. 

A female lobster and a female spider crab are caught during the day's dock program.


Great Things Come in Small Packages (Cuttlefish Eggs)

What has 18 tentacles, 9 beaks, 72 arms and thousands of color changing cells?
It’s the cuttlefish exhibit in the New England Aquarium’s Tropical Gallery!

Dwarf Cuttlefish (Sepia bandensis)

Located on the first level of the exhibit area, the cuttlefish exhibit is currently home to nine dwarf cuttlefish (Sepia bandensis). These small, four inch relatives of squids and octopuses are cephalopods, meaning “head-foot.” And they do look like they are just that: a head and a bunch of feet! Most noticeable on the front of their bodies are their two feeding tentacles and eight arms that they use these to snare prey, like shrimp and small fish. Once the food is caught, the cuttlefish breaks up the food with their hard beak and it’s snack time!

How many cuttlefish can you find?

Resembling small flying saucers, cuttlefish use a flexible fin and jet propulsion to move both vertically and horizontally in the water! They also have the most amazing ability to change their appearance with thousands of color-changing cells all over their skin. It’s thought that cuttlefish use their color changing abilities to aid in communication, mating and to mesmerize prey. Check out the video below … if you look closely, you will be able to see the cuttlefish change the color pattern of its skin!

And while this entry was being written, the cuttlefish went and did something that makes the exhibit even more amazing-they laid eggs! Each of the small, ink colored eggs contains a growing cuttlefish that will hatch in approximately 25-30 days. If you visit soon, you may still see the eggs. However, our aquarists will remove the eggs soon in hopes of hatching, and then raising, some new cuttlefish for the exhibit. Here's a good image that shows what to look for in the exhibit.

Cuttlefish Eggs (Steinhart Aquarium)

So come visit these tentacled, color-changing flying saucers. They might be small, but great things do come in small packages.



Rays of the Touch Tank: Leopard Whiptail Stingray

One of our most beautiful animals in The Trust Family Foundation Shark Ray Touch Tank is also one of our most elusive. The leopard whiptail ray (Himantura undulata) has an intricate skin pattern that certainly does call to mind its namesake, the leopard.

Photo credit: Marcel Burkhard via Wikimedia Commons

Leopard whiptail stingrays can grow to about 1.4 m wide. As with other whiptail rays, their tail is very long compared to their body and the animal's total length can be upwards of 4 m. These rays are found naturally in the Indo-Pacific region from the Bay of Bengal to Northern Australia.

These rays have a varied diet, but are thought to eat mainly mollusks and crustaceans. Like other rays they use their strong jaw to crush the shells of these animals to get to the soft animal inside.

Photo credit: Sam Cheng

When you visit the tank it may be hard to see this animal right away. However, if you're patient and look towards the back of the tank, you may be lucky enough to "spot" this gorgeous animal. I don't know of anyone getting to touch this shy animal yet, but you never know. If you do get super lucky and have the opportunity to interact with this animal, be sure to come back here and comment about your experience! Just be prepared for jealous comments from educators!



Just the biofacts: What is sandtiger shark skin made of?

When you visit The Trust Family Foundation Shark and Ray Touch Tank, you probably will have only a few seconds to touch a shark before it swims past you. But find one of our educators in the exhibit, and you could have a chance to spend a lot more time with some shark skin.

 A sandtiger shark in the Giant Ocean Tank

One of the biofacts that educators bring into the touch tank exhibit is a piece of sand tiger shark skin (shown at left). When you get up close to the skin, you can see that it has tiny scales called dermal denticles (“tiny skin teeth”). Dermal denticles point tailward, so when you feel shark skin from head to tail, it feels smooth, but from tail to head, it feels coarse like sandpaper. The denticles are also strong, giving the shark a flexible, armor-like skin. This helps reduce drag and allows the shark to move more quickly through the water.

If you take a closer look at the skin, you may find something else amazing. Look for small holes or pores—those are the Ampullae of Lorenzini. Located around the snout and under the mouth of a shark, these special organs can sense the electrical fields in the water, giving sharks their “sixth sense”! They help the shark find food and may assist in locating birthing grounds.

An up close look at the sandtiger shark skin showing the Ampullae of Lorenzini

Sand tiger sharks are listed as Vulnerable to Extinction due to capture for sport and by commercial fisheries. Many types of sharks have been hunted for their skin, which some cultures use as sandpaper or to make purses, wallets and shoes. They are also caught as bycatch in nets of other fisheries.

We can reduce the number of sharks caught by not purchasing shark-related items and by choosing seafood that’s caught in a sustainable way, reducing shark bycatch. Visitors can check our website for additional information on sustainable seafood choices.


[Learn more about sandtiger sharks in these posts from the Aquarium's divers blog: Why do sharks have so many teeth? How do sharks get a medical exam? and Does Myrtle the green sea turtle ever try to steal the sharks' food?]


Yellow Stingrays: Often Yellow, Often Not

A fun aspect of The Trust Family Foundation Shark and Ray Touch Tank is that, just like in the wild, there are several animals in the exhibit that require some extra effort to see, so you really never know what you'll encounter on any given visit. The ever-sociable cownose rays are pretty difficult to miss, but some other animals, like the yellow stingrays, can be trickier to spot.

Can you find the yellow stingray in the picture above? Below is a stingray that is feeling less camera-shy.

Unlike the free-swimming cownose rays, yellow stingrays are bottom-dwelling rays who stick close to the ocean floor. They use their fins to dig in the substrate, which is helpful both for digging up buried food and for burying themselves to hide from their own predators.

Watch a yellow stingray in action! This video was recorded was during a SEA TURTLE expedition to the Bahamas. (Learn more about SEA TURTLE here!) And check out the picture of yellow stingrays taken by an Aquarium diver in the Bahamas here.

Yellow stingrays can even change their colors to help themselves blend in more effectively with their surroundings, so they might be yellow one minute and brownish the next.

Next time you visit the touch tank, keep your eyes near the bottom to see if you can spot one of these camouflage experts. And remember, you might even find something that you weren't looking for.


Sharks of the Touch Tank: Coral Catshark

If someone says the word shark to you, what comes to mind? Unfortunately, for many the word conjures nightmarish images of large, toothy monsters straight out of the movies. In truth, most sharks are shy and elegant creatures that pose no threat to humans.

Of the 400 species of sharks in the world, most are less than 6 feet long and more than half of these are less than 3 feet long. Since they eat—or are eaten by—other animals, sharks are an important part of healthy oceans, no matter their size.

Take one of our resident sharks, the coral catshark (Atelomycterus marmoratus). Seldom growing larger than two feet, this Indo-Pacific species avoids predators in the wild by hiding in crevasses and under coral ledges where their spotted coloration helps them blend in to their surroundings.

(Photo credit: Ronnie Liew)

Here at The Trust Family Foundation Shark and Ray Touch Tank, the best place to see our coral catsharks are amongst our artificial mangroves where they are often among other equally elusive shark species.

(Photo credit: yvonne n)

After interacting with these animals in our touch tank, you may find yourself having a completely different view of sharks.

- Dave


Epaulette Shark: Dressed for Success

Throughout the world's oceans, we can find sharks of all different colors, shapes and sizes. Many of them have spots, stripes or other colorations that help them blend into their environment and hide from predators. Want to see some examples? Take a look in The Trust Family Foundation Shark and Ray Touch Tank to see some colorful characters.

Epaulette Shark (Monterey Bay Aquarium)

One of the most colorful sharks in the exhibit is our epaulette shark. Identified by the large black spots on their bodies, the epaulette shark gets its name from a wardrobe choice of Napoleon. It's true! Epaulettes are the shoulder pieces or large decorative items worn to designate military rank. In many paintings and descriptions, Napoleon is depicted as having large epaulettes.

Yellow epaulette (wikipedia)

Epaulette sharks are named after these shoulder pieces due to their two large black spots located towards the front of their body. Now while the sharks don't use these spots to designate military rank, they do have an important purpose. They are part of their camouflage!

You would think that those big black spots would allow for the shark to stick out. And that is exactly the purpose behind those spots! The sandy color of the epaulette shark’s body blends in with their sandy habitat, allowing for those large, dark spots to be seen easily. As a large predator swims by, the spots stand out and resemble the eyes of a large animal. Thinking that a larger animal lurks nearby, the predator will swim away, leaving the small epaulette shark in peace. Success—the epaulette shark will swim to see another day.

Epaulette shark hiding in mangrove roots

We all like to make sure that we dress for success and the epaulette sharks are no different. Come by the touch tank and see if you can find those dark eye spots throughout the exhibit!


No, That's NOT a Baby Hammerhead

One of the most common things we educators have heard while speaking with visitors at The Trust Family Foundation Shark and Ray Touch Tank is requests to touch the baby hammerhead shark. This is pretty much what we expected when we added one of our favorite animals to the new exhibit. But those sharks everyone asks about are actually called bonnethead sharks!

Bonnethead shark in The Trust Family Foundation Shark and Ray Touch Tank, photo credit: Keith Ellenbogen

Bonnethead sharks (Sphyrna tiburo) are in the hammerhead shark family, but deserve recognition of their own. They are the smallest species of that family, and their heads are shaped much more rounded than the stereotypical, more rectangular hammerhead shape. In all hammerhead species, this unique head shape is known as a cephalofoil. They sway this cephalofoil back and forth as they swim, using their very sensitive sensory and nervous systems to locate prey.

Hammerhead shark, photo courtesy: Barry Peters via Wikimedia Commons

Perhaps the most fascinating fact about bonnethead sharks is that they have been documented to reproduce asexually. In 2001, a female bonnethead at the Henry Doorly Zoo in Nebraska who had never had contact with a male gave birth to a pup. Genetic testing confirmed that the pup was identical genetically to its mother. This type of reproduction, previously unknown in cartilaginous fishes like sharks and rays, is known as parthenogenesis.

Photo credit: Keith Ellenbogen

The new touch tank is a great place for these sharks, since they are naturally found in coastal waters on both sides of the Americas. While they have been spotted rarely in New England waters, they prefer water temperatures above 70 degrees F.

So next time you’re at The Trust Family Foundation Shark and Ray Touch Tank, ask the educator on duty about the bonnethead shark. We love to teach visitors that they're not just another hammerhead!