WOODLAND PARK ZOO FIELD TRIP

I took the field trip to the Woodland Park Zoo on February 25 from 9 am to 2 pm. It was a mostly cloudy Sunday with a little bit of rain and sun here and there. I chose this field trip because I wanted to know more about the animals in Pacific Northwest because I came from Asia, so I was not familiar with the range of animals that live around here. I think it would be fun to get to know these animals from the other part of the world.

GRAY WOLF

Figure 1. Three gray wolves in the exhibit

Figure 2. A closeup of the gray wolf

Figure 3. A sign near the exhibit

Figure 4. Distribution of grey wolf

                We started at the gray wolf exhibit. I saw three wolves in total (Fig. 1). They were walking and grabbing meat scattered in their area. Then, I saw a sign on the railings of the exhibit telling the visitors not to howl at the wolves (Fig. 3). It indicates that enough people have tried to copy the wolf’s behavior to howl. Howling is their way to communicate with other wolves, to find their pack, and to keep strangers away. The ability to howl is probably as important to wolves as speaking is to humans. That is why wolf pups learn how to produce adult howls. They are also quiet walkers due to the pads under their paws. They walk very lightly based on their foot trace compared to their size. This adaptation allows them to walk on snow and to leave minimal traces. They have thick white/gray fur to keep them warm and blend in with the snow. Gray wolves are carnivores and predators. They mostly use their smelling and some hearing for survival. Therefore, I would expect their skull to have orbits facing forward, prominent sagittal crest, sharp teeth with large and sharp canines, complex nasal turbinates, and medium auditory bullae. They have mostly similar traits to other types of canines. Gray wolves look a lot like Siberian Husky dog. However, they are larger in size compared to dogs. Their distribution is limited as their habitat (wild areas) is shrinking (Fig. 4). They can be found in the Far North. However, gray wolves were reintroduced to Yellowstone National Park to control the deer population and return the wolves back to their former home. An adult wolf usually eats 4 to 7 pounds of meat in a day. Statistically, there is only 6.25% of success in moose-hunting for wolves; that is one out of 16 moose they chase. A question from the signs provided is how long a wolf pack needs to travel to find food in a day.

GREAT GRAY OWL

Figure 5. A great gray owl in the exhibit

Figure 6. Distribution of great gray owl

                Then, we moved to the great gray owl exhibit. I barely saw the owl because it blended in with the environment very well (Fig. 5), so I guess their color is one of their adaptations which works perfectly. I expected it to be asleep since it is nocturnal, but it just perched on a tree wide awake. The differences between great gray owls and snowy owls is their colors and its hunting behaviors. Great grey owls have silver grey feather to blend in with trees and the dark night. Unlike snowy owls, great gray owls are nocturnal. They are silent hunters with noiseless feathers. Their yellow eyes provide incredible sight at night. Their hearing is even better. Their head is large and flat on the face with skewed ears to create a resonance chamber which enables great grey owls to exactly pinpoint their preys. Great grey owls are distributed across the north, such as Northwestern America and Canada (Fig 6). Their adults are around 20 to 35 inches in length and around 1 to 2 kg in weight. I would expect to see very large orbit facing forward, simple nasal turbinates, and no sagittal crest on a skull of a great grey owl. I would expect to see a bigger skull for great gray owls compared to snowy owls. A question from the signs provided is what type of animals they usually eat.

PORCUPINE

Figure 7. A porcupine in the exhibit

Figure 8. Distribution of porcupine

The porcupine was only out for a very short period (Fig. 7), I guess it was shy or about to be fed. Gwen told us we got lucky because it was usually way more stinky around the porcupine exhibit. Porcupines secrete smelly pheromones into the air to keep predators away and mark their area. They also have sharp quills for defense. These quills take less force than needles to pierce a skin, and they are harder to remove. According to the sign, they are usually found in trees. Their distribution is around Canada and Alaska (Fig. 8). They are closely related to guinea pigs; both have a very reduced vestigial tail. Porcupines are herbivorous rodents. They eat leaves and other parts of plants. When plant matter is scarce during winter, they eat barks. I would expect to see herbivorous teeth: large flat incisors, flat molars, and no canines; orbits on the sides, typical for preys; and no sagittal crest on a skull of a porcupine. A question from the signs provided is whether porcupines can shoot their quills.

BROWN BEAR

Figure 9. A brown bear in the exhibit

Figure 10. Comparison of bear skulls and footprints

Figure 11. Distribution of brown bear

The most interesting thing in the brown bear exhibit is the display of its skull and footprint (far right) in comparison to other bears (Fig. 10). The skull has medium-sized orbits facing forward, typical for predators; a quite long snout and complex nasal turbinates, indicating they have great smelling sense; and very prominent sagittal crest, indicating very strong jaws. I saw 2 of them: Matt and Steve. One of them is laying right behind the glass wall (Fig. 9) so I could see it clearly. Both were sleeping or just laying down. They have thick fur and fat layer to keep them warm in cold temperatures. They are omnivorous predators so they can eat anything available on every season. They have long claws to dig and grab their prey (salmons). Brown bears can be found in the Northwestern corner of America, Alaska, Northern and Western Canada (Fig. 11). The adult males are bulkier than the females. The males have wider face and smaller ears than the females. A mother typically gives birth to two cubs at once (twins), each weighing less than a pound. Brown bears diet mostly consists of vegetation, such as plants and berries. I also saw sloth bear, which I will compare and contrast to brown bears. A question from the signs provided is why cubs usually spend 2 to 4 years with their mothers.

RIVER OTTER

Figure 12. A river otter swimming in the exhibit

Figure 13. River otter statues

Figure 14. An example of river otter's den

Figure 15. Distribution of river otter

Next to the brown bear exhibit is the river otter from the Mustelids family. The most interesting thing in this exhibit is seeing the otter swam back and forth behind the glass wall while little kids chased them down (Fig. 12). Also, there were 2 standing statues of the river otters (Fig. 13). Otters live near clean water with many fishes for them to feed on. They secrete natural oils so that their fur does not absorb much water. The fur also keeps them warm. In winter, they will mostly curl up throughout the day to keep themselves warm. They have webbed toes and long tail to help them to paddle and control their swimming in water. They also have big lungs to store air while they swim under the water. However, they are not born swimmers. Newborn otters have to learn how to swim and not be afraid of water. I would expect to see medium snout, complex nasal turbinates, and small-sized orbits facing forward on a skull of a river otter. Compared to Asian small-clawed otters, river otters catch food with their mouth, while Asian small-clawed otters catch food with their limbs. This is due to the difference in their legs: river otters have webbed toes and Asian small-clawed otters have digits, so they can grab their food with those fingers. However, they have the same body forms, fur, and overall appearance. River otters live in a den (Fig. 14) near water stream made by other animals, such as muskrat, woodchuck, and beaver. A question from the signs provided is what river otters do to keep themselves warm during wintertime.

COMPARE AND CONTRAST

Figure 16. A sloth bear in the exhibit

I am going to compare and contrast brown bears (Fig. 9) and sloth bears (Fig. 16) from the Ursidae family. The brown bear exhibit is located in the Northern trail, while the sloth bear exhibit is located in the tropical Asia trail. Both are omnivores, but their diet mainly consists of vegetation, such as plants and berries. They are powerful predators, so I would expect to see orbits facing the front and prominent sagittal crest on their skulls. They walk on four but can also stand on their back feet. They have fur to keep them warm. They have long snout and complex nasal turbinates, which make their smelling sense great. They have claws for digging instead of defense, but the shape of the claws is different.

Brown bears are much bigger in size than sloth bears. An adult male brown bear can weigh over 1,000 pounds, while an adult male sloth bear only weighs around 300 pounds. Brown bears have plain brown fur, while sloth bears have black fur with a white V-shaped pattern on their chest. Brown bears live in the forests and mountains usually near a water stream, while sloth bears live in forests with minimum water stream. That is why the zoo place water stream in the brown bear exhibit, but not or minimal in the sloth bear exhibit. Brown bears live near the stream to catch fishes, mostly salmons. Instead of fish, sloth bears usually eat insects, such as ants and termites. To adapt to the dust in dry areas, sloth bears can close their nostrils completely to avoid dust or small animals from getting into their nose. Brown bears have long blunt claws used for digging, while sloth bears have curved sharp claws used for digging and sometimes climbing. Brown bears have extra layers underneath their fur to adapt to the cold temperatures, while sloth bears who live in warm tropical areas don’t.

Their ancestral traits include large mammals, very short tail, omnivorous teeth, prominent sagittal crest, long snout, small eyes, thick fur, and small rounded ears. Derived traits of brown bear include straight long blunt claws, hump on top of its shoulders, and brown fur ranging from light brown to dark brown. Derived traits of sloth bear include long shaggy hair around its face (mane), white V-shaped pattern on its chest, curved sharp claws, and insect-eating teeth (missing two middle incisors to suck insects).

REFLECTION

                One thing I learned on the field trip is the different adaptations of animals mostly to the condition of the habitat they live in and resources availability. Each animal I saw has their own unique adaptations, and they make sense considering where they live in, what they eat, or how they live. Even the animals from the same family, like brown bears and sloth bears from the Ursidae family, have different traits and adaptations because they live in different parts of the world, which makes them adapt to the different environments. These adaptations help animals to occupy different niches, so not all of them are clumped at one place. This is why different parts of the world offer a different variety of animals. This field trip changed my perspective on animal biology. I never thought animals could be so diverse, at least not in the closely related ones. I didn’t think these traits and adaptations were very important to these animals. I used to hate going to the zoo because I thought it was very boring. However, after taking the animal biology and learning about these little traits and adaptations, I appreciate the opportunity to go to the zoo and see animals closely more than I ever did. I’d love to explore more about the animal diversity around the world if I ever had the chance. I now think it’s very interesting to study animal biology because there are always new things to discover.