Gentle giants

Giraffes are the tallest terrestrial vertebrates (males stand about 20 feet tall, females slightly less), which opens up leafy resources other browsers like the stately kudus lack, but also present a host of problems for survival.

Giraffe feeding on high vegetation

Stretching to reach those last few leaves on the acacia tree–food is scarce in the dry season in Botswana.

That long neck that makes up 50% of their height makes it a challenge to pump blood against gravity up to the brain.  Consequently, their highly muscular, thick-walled heart has to generate more than twice as much pressure as the human heart does. (Giraffe blood pressure runs about 280/180–normal human blood pressure is about 120/80 or lower).  That’s fine for getting blood to the brain, but blood flow is all downhill to the feet, so how do giraffes keep from getting swollen ankles?  With tight-fitting, elastic skin that acts like compression stockings, the kind they give heart patients to wear.

Giraffe in Botswana

The tallest object in this environment, but just look at those skinny little legs that support the massive upper body mass.

Their height also gives them a bird’s eye view of their surroundings, including predators perhaps lying in wait in the grasses below, but that same height advantage becomes a disadvantage when giraffes need to awkwardly bend over for a drink or food on the ground.

Giraffes feeding on a carcass in Botswana

Two giraffes were taking turns getting a bite of a decaying carcass. They eat bones and cartilage left by scavengers to obtain minerals lacking in their leafy diet.  The giraffe on the right has spread its front legs wide to enable its head to reach the ground.

Just getting into position for a drink or a bite of something on the ground is a mechanical problem in itself.  But lowering its head below the level of the heart poses a great risk of cerebral hemorrhage.  To combat this potential physiological disaster, arterial pressure sensors detect changes in head position and cause an immediate decrease in heart rate and heart contraction strength to decrease blood pressure.

Great vertical height poses problems for other organ systems as well.

Male giraffe feeding on acacia

Giraffes are ruminants, and like cattle, they regurgitate what they have browsed to re-chew it into smaller pieces.  That requires a long, very muscular esophagus, capable of returning food from the stomach to the mouth.

Very long necks require very long nerves running from the brain to the periphery.  For example the nerve that stimulates the vocal cords and muscles that enable swallowing is 5-6 feet long!  It better conduct very fast, or food will go down the wrong tube (i.e., the trachea) when they swallow.

Giraffes love to browse on acacia leaves, but the plants have a great plenty of protective thorns, which the giraffes’s almost prehensile lips and tongue seem adept at working around.

Female giraffe, showing tufts of hair on the horns

That soft upper lip is highly mobile. Inside the mouth is a 20 inch long, highly muscular tongue that can delicately wrap itself around tiny leaves but avoid prickly thorns.  And just look at those long eyelashes, and big brown eyes.  Isn’t she a beauty?  (Hairy tufts at the end of her knobby horns indicate this is a female).

With their graceful walking stride and elevated height, giraffes just epitomize the “gentle giant” title.

The river horse

Probably one of the oddest looking and most intimidating animals in Africa is the hippopotamus (literally translated, river horse).  Hippos are uniquely amphibious, spending most of their day in the water but their nights on land foraging.

Basking hippos, Kruger Park, South Africa

Although occasionally, hippos come out for a sunbath on land.  Their skin may be six inches thick but is still subject to sunburn.  Unlike elephants that throw dirt on their wet skin to protect it, hippos secrete an oily substance from their skin that reflects ultra-violet light, a “hippo sunscreen”.

Hippos foraging at sunset, Chobe national park, Botswana

Out on land just at sunset, the nightly grazing on grasses begins. Hippos might travel 6-10 miles to find enough grass to sustain them for one day.  But surprisingly, this 1.5-2 ton animal eats just 80-100 lbs of food per day, because it has a multi-chambered stomach (like cows) which increases its digestive efficiency.

Despite their short, stubby legs, flat, webbed feet, and rotund girth, hippos can move quickly on land, up to 20 mph (30 kph), at least for short distances, so it would be a mistake to try to outrun one.  Their bulky weight is supported in water of course, where they seem much more “graceful”.

A pod of hippos

Eyes, ears, and nostrils are displaced to the top of a hippo’s head, so they can keep tabs on their environment while floating (well, actually while standing on the bottom).

A pod of hippos

Usually one bull hippo controls a stretch of river or lake area in which dozens of females, calves, and bachelor males hang out in social groups.

Hippos are aggressive, especially when they feel threatened, and their great bulk and quick movements mean humans should maintains respectful distance.  But sometimes, a hippo surfaces for air closer than is comfortable, requiring a speedy retreat.

Hippo in Okavango delta

Fortunately, not an aggressive one, it left our little boat alone.

Hippo yawn, or threat display

But this one may be warning us away, or it could just be a bored yawn.  Those projecting lower canine teeth can grow to 1.5 foot length in big bulls, and do serious damage even to thick-skinned hippos.

Hippo yawn, or threat display

No, this looks more like a threat display, with head raised above the water, and jaws open almost 180 degrees. It kind of reminds me of the Animal on the Pez candy dispenser.  The only reason to open its mouth this wide must be to intimidate or do physical damage to another hippo.  Sort of a “my teeth are bigger than yours” contest…

Small front incisors are used to cut the grass, rear molars are useful grind it before passing the food into the chambered stomach.  Unlike cows, hippos don’t regurgitate the mix and chew their cud.  Projecting canines are used as weapons.

But the most amazing thing to me about hippos is that they are not at all related to the other, diverse, grazing ungulates of the African savanna! nor are they at all related to horses (despite being called the river horse).  Instead, there is clear genetic evidence that their closest relatives are the whales, dolphins, and porpoises.  The common ancestor of hippos and whales branched off well before grazing animals like antelope and horses appeared in the fossil record.

Just in time

We returned from Southern Africa about a week ago, just in time to appreciate the splendor of the fall season as it was reaching peak color.  Walking around my neighborhood and the local lakes was a feast for the eyes.

fall color-birch tree

the birch tree my front yard

fall color-street scene

fall color along the street

fall color-Minnesota woods

fall color-Minnesota woods

Minnesota fall color-lake reflection

Colors reflected in the lake water

fall color in an office building

Fall color reflected in the windows of an office building. How do people that work in this building keep their mind on their work?

Monkey business

If only they could talk, what would they say?

Chacma baboon

“I’m looking for just the right place”

Chacma baboon

“Ahhhh……”

Young vervet monkeys

“Hey, cut it out! Stop pulling my hair”

Young vervet monkeys

“He started it!”

Young vervet monkeys

“Sorry, but this is private”

Male vervet monkey

“Yeah, so what if my privates are showing!” 

Not your typical secretary!

What do you call a cross between an eagle and a crane?

African fish eagle

Suppose this bird (a fish eagle or similar eagle) bred with…

Sandhill crane

A bird like a Sandhill Crane (photographed October 2013 in MN).

The result might look something like this–a long-legged (like the cranes), raptorial (like the eagles) bird called the Secretary Bird.

Secretary bird (from Wikipedia by Yoky)

Secretary bird (from Wikipedia by Yoky).  Extremely long legs allow this strange-looking terrestrial (rather than aerial) predator to travel through tall grass scaring up potential prey, like insects, mice, snakes, lizards, etc. which it quickly immobilizes with its raptorial foot or beak.  Interestingly, the legs are so long and their neck is so short, they have to stoop over to reach the ground with their beak!

It must have been a challenge for early taxonomists to classify this bird, but anatomical characteristics like feet (and later genetics) allied the bird with hawks and eagles, not cranes.

Raptorial feet (from encyclopedia Brittanica)

Clearly, the feet indicate the secretary bird’s (bottom center) raptorial relationship.

But why the name, Secretary bird?

Secretary bird at Hwange national park, Zimbabwe

It got its name from the quill feathers that stand out from its head like the pencils or pens that secretaries used to stick behind their ears or in their hair-dos to have easy access to writing implements.

On our early morning safari drive in Hwange national park in Zimbabwe, we found a very amorous couple of secretary birds just getting off their nightly roost and cementing their pair bond before departing to forage that morning.

A pair of secretary birds on their roosting nest

Rise and shine, it’s 6 a.m.

Secretary birds from Hwange national park, Zimbabwe

A little billing and cooing between the two birds…is he whispering into her ear?

Secretary birds from Hwange national park, Zimbabwe

Before he jumps up on her back to ensure his contribution to the next generation.

Secretary birds from Hwange national park, Zimbabwe

And a few moments later, he is on his way again.

They will spend most of the day on the ground, searching the open savanna for prey, and then retreat to their nocturnal roost at sunset.  A pair might stay in the same area year-round if there are sufficient resources to raise a family.  They rarely migrate around their sub-Saharan environment.

What’s for dinner: fish, snake, or chicken?

We saw quite a few birds of prey on our tours of Southern Africa, but witnessed very few of their attempts at predation.

African fish eagle

Fish eagles, like their North American  cousins, the Bald eagle, are patient sit and wait hunters of open water near streams, marshes, and lakes.  We saw lots of them sitting on a high perch, but none of them actually hunting, or catching anything.  Like ospreys, they have specialized scales on their toes for grasping slippery fish.

Bateleur eagle, Okavango delta

Bateleur eagles are smaller-bodied than fish eagles with very short tails. They hunt primarily birds (pigeons and grouse) in open savanna country. Red face and gray and black wings distinguish them from the other, mostly brown eagles.

Walhlber's Eagle (top) and Tawny Eagle (bottom)

Two species of eagles on the same tree:  Walhlber’s Eagle (top) and Tawny Eagle (bottom).

Tawny eagle

Tawny eagles are quite variable in color (this is a darker form).  Its diet is largely made up of carrion, but it also feeds on a variety of small mammals in dry scrub and savanna areas.

Wahlberg's Eagle

Wahlberg’s eagle doesn’t discriminate in its food choices: reptiles, birds, and mammals make it into its diet. However this bird prefers to hunt the woodland instead of the dry, open steppe, so it is strange to find these two species together here.

Sightings of eagles were common, but smaller hawks were rarely seen in the acacia woodland or the open grasslands.  Instead, that ecological niche of small, mobile bird of prey seems to be taken by Yellow-billed Kites, which we saw frequently and everywhere, as they cruised over land or open water in search of a snack.

Yellow-billed Kite

The tail flares and twists to enable the bird to change direction. They rarely need to flap their wings.

Yellow-billed Kite

They hunt for small fish and invertebrates along the shore, but won’t turn down a nice meal of snake, lizard, bird, or mammal if they find one. Apparently carrion is also acceptable, which makes them true “meativores”.

A pair of secretary birds on their roosting nest

We found a pair of secretary birds on their roosting nest just at sunrise.  This nest is for nocturnal use, not for raising chicks.  These long-legged, terrestrial birds of prey can be confused with cranes, which they resemble, but genetically, they are lumped with the eagles and hawks.  They are diurnal predators of reptiles, insects, and small mammals, which they scare out of the grass by stomping around on the vegetation.

more on the adventures of Secretary Birds tomorrow!

Babies of all kinds

The savanna grass was tall and golden during our safari, often obscuring our view of the interactions of mothers and their babies.  Tall grass is probably conducive to keeping the youngsters hidden from potential predators, but mothers also seem to keep close watch, and touch, with their young ones.

Baby elephant seeks protection under its mother at the watering hole

Notice how this very young elephant is completely surrounded by its mother’s bulk, as they both get their evening drink on the Chobe river.

Mother elephant with two youngsters

At a watering hole in Kruger Park, a mother elephant keeps tabs on her two offspring by touching them with her tail or her trunk.  The youngsters, in turn, intermittently touch her as well.  Elephant skin must be quite sensitive because there was a lot of touch communication going on as they bathed.

Mother baboon carrying her baby

Primates often carry their babies around for some time after birth, due to their immature development. Babies seem to have no trouble hanging on, even upside down, without the aid of a sling or Becco carrier.

Baboon baby

Getting a view of its world from below…

Baboon mother and baby

A more typical pose of mother and baby sitting in a tree.

Hippo mom and baby

This hippo mom really dwarfs her week old youngster. I wonder how difficult it is to find the milk faucet on mom’s underside?

 

Hippo mom and baby

Hippo baby was a little unsteady on land, but mom was hungry so the baby followed her ashore, staying close by her side, and nosing her every so often — for security?

Sable antelope mother and kid

Sable antelope youngsters are probably quick on their feet soon after they are born, but just in case, mom sports a wicked set of spiked sabers to defend against would-be predators.

Zebra mother and young

Like the antelope. Zebra youngsters are good runners, and parents kick and bite as well. A zebra herd would stick together tightly when threatened, with the youngsters in the center of the herd.

Faces only a mother could love

There is another “big five” among African animals–the five ugliest animals: hyena, vulture (which one?), wildebeest, warthog, and Maribou stork.  I’m not sure what constitutes “ugly” status, but it might have more to do with behavior than actual looks.  Scavenging for a living is apparently not quite as glamorous as true carnivory.  However, what would the landscape look like with a lot of partially eaten carcasses just lying around, smelling bad?  Scavengers perform a vital service!

Hooded and white-backed vultures on an elephant carcass

Bald-headed birds seem less beautiful than fully feathered ones, but if you are going to stick your head inside a bloody carcass, then bald is practical and easy to clean. Hooded and white-backed vultures clean meat off an elephant skull, along with Pied Crows (also scavengers).

Maribou storks feeding on a Cape buffalo carcass

Maribou storks scavenge what little flesh remains on a Cape buffalo carcass.

Maribou stork

There is nothing beautiful about the Maribou stork’s face. The bill seems disproportionately big, and those red puffy areas on its head make it look diseased.

Spotted hyena from kids.britannica.com

We didn’t see any hyenas, although they do roam the grasslands of Southern Africa. Is it their odd stance (sloping shoulders), slobbery faces, vicious behavior, or scavenging habit that makes them part of the all-ugly team? (Photo from kids.britannica.com)

Scavenging alone is not enough to qualify for the ugly five, because a couple of vegetarians made the team.

Wildebeest in Kruger national park, South Africa

Just minding their own business, a herd of wildebeest cruise the grassland in search of something nutritious to eat. They are really just lion bait.

Wildebeest in Kruger national park, South Africa

Other antelope have short horns, or manes, or hair running down their necks to their chest, but not such long noses or beards, like this Blue Gnu.

Greater Kudu males

Wildebeest need to take a lesson from the stately elegance of Kudu males.  Short nose, no beard, better posture!

Warthog and young

And lastly, the ungainly warthog, whose ropey tail and oversized head make it a comical-looking creature. Mother warthog leads her offspring away by waving her tail like a flag for them to follow.

Warthog male

What does an animal need a huge head like this for?

More big cats

Our safari guides have the most amazing eyesight.

Leopard in a tree

Not only did they spot the track of the big cat leading up to the tree in the distance, but they spotted the cat up in that tree (arrow).

Tracks of leopard dragging an impala

Cat footprints overlain by the drag marks of the hooves of its prey, in this case an impala.

Leopard snoozing on a branch

With binoculars, I could finally see that there was a leopard zoned out on a branch of the tree.

Leopard resting on a tree branch

Although we were pretty far from this guy, he woke up momentarily to check for potential threats to his morning nap.

Impala cached in a tree by a leopard

After carefully scanning the branch on which the leopard was snoozing, I found the impala carcass the leopard had dragged up the tree. No wonder he needed a nap after all that exertion!  Just the impala head hanging down over the branch is visible.

Leopards are one of the most adaptable species of the large cats.  They live in a variety of habitats in Africa and Asia, and can capture a variety of prey.  Impala are numerous throughout most of the national parks in Southern Africa, and their dehydrated carcasses are often seen hanging from the branches of large trees.  Big heads with strong jaws and neck and shoulder muscles allow these cats to climb large trees with their prey to keep them away from lions, hyenas, and vultures.  But it must be tiring work!

Leopard snoozing on a tree branch

Exhausted!

The Big Five

One objective for most tourists who visit Africa is to tick off the “big five” from their list of animal sightings:  lion, leopard, elephant, rhino, and Cape buffalo (how the cheetah got left off this list is a mystery to me).  Our guides were not only eager to find these animals for us, but to find them early in the day when they were still active, so we were usually out driving the roads of the national parks by 6 a.m.

Our reward for our early mornings was being able to see more of the natural behaviors of these fascinating animals.  Watching sleepy lions in the zoo pales in comparison to  the excitement of seeing a lion pride feeding on a fresh kill (in this case an unlucky young bull elephant) just meters away from our vehicle.

A pride of lions feeding on a young bull elephant

We counted 3 adult females, 5 sub-adults, and three small cubs feeding on this young elephant, killed just hours earlier.  Adults feed first, followed by sub-adults, and then smaller cubs.  If a male was with this pride, he would have been the first to feed, whether he participated in the kill or not.

A pride of lions feeding on a young bull elephant

The intensity of the her direct gaze is a bit unnerving. This female ensured that her cubs were getting some choice bits to eat by standing over them.

A pride of lions feeding on a young bull elephant

Clean-up time comes after the feast.

Lioness seeking shade after a big meal

After feasting, it’s time to find a shady spot for a rest.

Male lions at rest under a rain tree in Hwange Park, Zimbabwe

Sometimes it was just the scene itself that was captivating, like these two young male lions resting under a rain tree.

Male lions at rest under a rain tree in Hwange Park, Zimbabwe