Categories
Nature

Ocean Traveller

Ocean Wanderer at sea
Turtle at sea. Photo by Marcello Rabozzi from Pixabay.

Our ocean traveler may spend around 10 or more years in the deep blue. These years are referred to as the ‘lost years’ being from when the hatchling enters the water until it returns to the same beach to breed.

Our turtle stands to live as long as 50 to 80 years or even more with scientists guessing a century might not be impossible, but lets look a little deeper into its time on this planet and the risks it faces.

Firstly our little turtle will start life underground having broken out of its egg using a special ‘tooth’ called a caruncle. This would be 5 to 6 weeks after the eggs being laid (around 50 to 200) and meticulously covered by the mother. The babies would be predominantly male or female depending on the temperature, as is the case with crocodiles, also a reptile. Once the surface is reached it becomes a race to get into the water with everything imaginable trying to eat them, from gulls, to crabs to fish in the water, to hawks etc. What a welcome into the world!

As if that’s not enough – they head for the natural light and white waves when the hatch. If the areas developed they often head the wrong way, aiming towards human development lights.

Turtle Hatchlings. Photo by skeeze from Pixabay.

How many make it to adulthood?

Estimates very from 1 in 1000 to 1 in 10000.

The turtles use their feet to swim and unlike their land based relatives, the tortoise they have streamlined shells for swimming. tortoises generally have much rounder shells which helps them get back onto their feet. Turtles being in the water most of their lives don’t need this adaptation. Another difference is with the leatherback is that they have a softer shell than their land terrestrial and other sea relatives. Lastly, Most sea turtles cannot retract their arms and heads into the shell.

Turtle in the deep blue. Photo by emipres from Pixabay.

So the big puzzle is what happens in the 10 to 12 years that our juvenile turtles spend in the deep blue sea…

Well, even in this day and age with loads of technology we still don’t know exactly. We do know that they travel vast distances on the ocean currents, drifting on the surface or spending long times in massive seaweed beds. The advantage of heading so far out to sea and getting away from the continental shelf is most likely that they avoid most predators such as sharks and birds.

One of the studies undertaken found a baby turtle had traveled 700 miles (1100 km) in 11 days !

So what do they eat out there?

Their diet is also dependent on their specie, with leatherbacks eating mostly jellyfish (and sadly, plastic bags that look like jellies) and hawksbills eating predominantly sponges. Others eat a combination of plants and animals. The differences are depicted in the shape and size of the mouths.

Turtle eating sea grass. Photo by ivabalk from Pixabay.

Sea turtles cannot breathe underwater but they can hold their breath for an impressive 4 to 7 hours!

They can also drink sea water -this is because they have a gland that allows them to excrete excess salt thereby maintaining the salt balance in their bodies.

Categories
Nature

Weaving for Love…

Southern or Masked Weaver male
Masked Weaver or Southern Weaver male. Photo by Sheldon_55 from Pixabay.

This brightly colored resident of Southern Africa has an incredible skill being able to weave a sturdy nest from strips of grass, bamboo or palm leaves. He goes through a whole routine to find a mate by firstly building the nest, which in itself takes around 15 hours. Then he does a whole lot of singing and fluffing his feathers around shaking them in a wings spread courtship display.

Eventually he will get a females attention and he will flutter around full of excitement, making an incredible fuss, often having to see off other would be suitors in the process. Each time he displays he moves closer to the nest he has built until eventually hanging from the entrance at the bottom of the nest and flapping his wings, all the time singing away.

Weaver nest display
weaver courtship display at base of nest showing entrance. Photo by Daniel Albany from Pixabay.

He then flies away from the nest opening, inviting her to inspect the house that he has built for her. This might take a while with multiple repeats to and from the nest at any point she may become bored with the whole charade and fly off leaving him to start searching for another female.

If he does manage to get her to inspect the nest, she will grasp the underside of the nest with her feet and then enter it from the opening near the base. She will disappear into the nest while he watches, ever hopeful…

If she thinks its good enough it remains as it is and they will start to prepare it by lining it with soft feathers in preparation for breeding…

However, if she doesn’t like it, nobody else will either !

She lets rip !

Tearing the whole thing apart before leaving him all alone and probably wondering what he did wrong!

Never the less, as the master of resilience, he starts again and builds yet another nest ( he may build up to 25 in a season) before trying to entice the next female. He may need to go through this process a number of times in a single season before being accepted.

Once successful and the kids have left home, he may start the whole process again having multiple broods in a season, each one with a different female.

These nests are typically built near water, often in the long dangling branches of the weeping willow tree, or a palm tree, other times in the reeds and even in suburban gardens.

Weaver nest built in reed bed
Weaver Nest built using reeds. Photo by Lynn Greyling from Pixabay.

As can be seen the nest built using reeds is pretty straight forward but the one hanging from a tree is sort of upside down with the entrance at the bottom. However, his design work has catered for the likelihood of the eggs rolling out by making the living area a little recessed from the entrance and a little bit lower.

So why build it like this in the first place?

The advantage of the entrance being below should be seen in conjunction with another feature. He has stripped off all growth on the branch that his nest is hanging on, but why?

The answer is snakes, by having no growth on the branch it makes it more difficult for a snake to access the nest, especially with the entrance below. Its not impossible, but rather difficult.

As a further defense, these little birds often create colonies and if a predator is in the vicinity they make an incredible noise and indulge in flying towards the predator in an intimidating manner.

After all of this the female will lay 2 beautiful blue eggs but could be up to 5 in number. Then it will take 12 days to hatch them. At this point the male helps with feeding the chicks and after 21 days they are ready to fledge. The main diet of these birds are insects, grain and even nectar, they readily accept picnic scraps and other hand outs.

Weaver eggs
Weaver eggs. Photo by Dennis Larsen from Pixabay.

Weavers are the only birds that are able to tie knots!

Categories
Nature

One Flight, Two Mediums.

Gannets courting
Gannets by Topi Pigula from Pixabay

Both beautiful and versatile the awesome Gannet.

I have always been amazed at how some birds can fly, dive into water, swim almost with almost equal dexterity, catch prey specifically designed to operate in its own medium and then surface with a its catch, often equal to a large percentage of the birds own body weight and then fly home.

Gannets are found in both the Northern and Southern Hemisphere. They typically live in large colonies with a constant landing and taking off on foraging trips. They fly up to 300 miles (480 km) in a day at a speed of roughly 45 mph (70 km/h).

This bird has some pretty cool features to be able to operate the way it does.

It can spot prey up to about 150 ft (45 m) above the water but would normally operate at 30 to 65 ft(10 m to 20 m). This is assisted by having its eyes far enough forward to allow binocular vision enabling better judgement of distance.

Our gannet typically dives into the water, folding its wings back and diving at up to 60 mph (100 km/h). Our gannet doesn’t have external nostrils, but internal. This ensures that it does not fill the nostrils with high pressurized salt water when entering the water.

Further to this our bird has a reinforced skull and sternum with air sacs under the skin in the face and chest which is a bit like bubble wrap and absorbs a lot of the entry shock.

The birds vision switches in a split second as it enters the water effectively blocking out ultraviolet light that distorts the position of fleeing prey.

Once underwater our gannet continues down to around 4 meters which effectively limits the fishes escape routes by cutting off the deep water one, being the most likely escape route. The school of fish would move even closer to the surface and get more concentrated with some jumping to try to escape.

At this point our gannet starts its underwater hunt swimming after the frightened fish. They are able to swim an additional 45 ft (15 m) underwater. They then swallow the fish underwater before surfacing to fly away.

In all this chaos, given that there are other predators and gannets are also stealing each others catches underwater. A Massey University study has found that some gannets had been killed when two birds dived for the same fish. The first one on target being the unfortunate one due to the second birds beak piercing the first birds neck. In addition there are also high speed impacts into either each other or into fast moving fish.

From the reproduction side gannets take about 5 years to reach full maturity. They pair for long periods but sometimes separate although separation is mostly when a partner dies.

gannets nesting
Gannets nesting. Photo by Yi Wei Sum ffrom Pixabay.

They lay a pale blue egg and both parents hatch and nurse the chick with the egg on top of their webbed feet to keep it warm. If a chick of less than 8 days old is lost the parents generally start again but beyond that they would wait for the next season.

Newly hatched chicks are black and eyes are closed at birth, after about 2 to 3 days the eyes open. Young birds are fed regurgitated fish and will fledge at around 100 days. the fledging process involved heading for a nearby cliff top and they could remain there for anything between 3 hours and 3 days before taking their first flight.

Gannet with fluffy baby
Gannet and chick. Photo by Nydegger René from Pixabay.

The juvenile bird will return to the colony from about three years old and breed at around 5 years.

Categories
Nature

Ugly but fast

Warthog
warthog tusks

The Warthog named after the four warts found on its face which are used for defense is found over much of Africa’s Savannas. These warts consist of a combination of bone and cartilage. The animal has a reputation for being able to fight although it normally only does that if it has no other option.

When threatened the Warthog runs with its tail pointing straight up in the air. It normally heads for its burrow which it reverses into so it is able to defend its position with its very potent head and tusks. Warthogs can reach speeds of up to 30 mph or 48 km per hour and are very nimble on their feet. Although Warthogs are very competent diggers, they usually take over a burrow left by another animal, the aardvark (direct translation is “earth pig”)which is Africa’s ant eater.

Warthogs spend most of their time digging for roots, grass and berries but also eat prey such as small mammals as well as birds. They will even scavenge for carrion when the opportunity presents itself. The spend a lot of time in a kneeling position to feed, this is due to their necks being short and their legs are relatively long by comparison.

warthog feeding
kneeling warthog

The Male warthog is a boar and the female is a sow with young warthogs being called piglets and groups of warthogs are called sounders.

Although warthogs are prolific breeders their numbers are contained by predation with the main predators being lion, leopards, cheetah, hyenas, crocodiles and wild dogs. Their chief means of defense is speed and getting into a defensive position by reversing into a burrow. They are however, very capable fighters with dangerous tusks and a solid body.

During breeding season boar on boar conflict is common as they fight for conjugal rights. In general they are not territorial but do occupy home ranges. Warthogs have a polyandrous mating system with males and females having multiple partners.

Typically a sow’s litter would consist of between two and eight with the norm being between two and four piglets. Warthogs are known to foster other piglets if they lose their own litter. This behavior is termed ‘allosucking’ and makes them co operative breeders.

Gestation period is roughly 150 to 180 days with the piglets spending six to seven weeks in the burrow. Once they venture into the big wide world the mother will nurse the piglets until 21 weeks old at which point they need to fend for themselves. It will take a total of about 18 months for them to reach sexual maturity but will only gain access to females at around 4 years.

They can expect to live up to between 7 and 11 years but have been known to reach 18 years !

warthog with main
Categories
Nature

Head in the clouds

Giraffe on road
Photo by H Bieser from Pixabay

The tallest giraffe was almost 5.9 m or 19 odd ft tall but are generally around 5.5 m tall. Each giraffe has a unique pattern which also gets darker as the animal ages. The male is called a bull, the female a caw and the baby is a calf.

Similar to its relative, the okapi, our giraffe also has two ossicones and eats mostly leaves. The big difference in eating habits (our giraffe eating mostly acacia leaves) relate to the environment, with the giraffe being a Savannah based creature where its long neck gives it an obvious advantage. The long tongue well suited to curling around and plucking leaves from trees. The tongue is typically 45 cm or 18 inches long.

giraffe tongue
photo by RJ McSorby from pixabay

The giraffe is the tallest animal and the largest ruminant with four stomachs, as is the case with cattle. The giraffe is normally pretty good at looking after itself and very capable of inflicting serious damage to a predator that doesn’t dodge the it’s solid hooves.

So what about that neck? well its too short to enable the giraffe to drink water without spreading its front legs but has some adaptations to regulate the rate of blood flow to the brain. When the animal bends down the blood rushes to the brain without much interference but when it raises its head suddenly, the blood vessels constrict which stops the blood rushing from the brain and thereby ensuring the animal does not faint.

In addition to this the blood pressure in the lower legs is regulated by tight thick skin in order to compensate for the massive weight and fluid above them.

As one would imagine, all this blood flow would need a pretty good heart which weighs in the region of 11 kg or 25 lb and beats at around 150 beats a minute. The length of the heart is around 60 cm or 2 ft long.

baby giraffe
Photo by : Ben Kerckx on Pixabay.

The giraffe only needs to drink water once every few days, normally less than three. This is due to the efficient system that it obtains most of its moisture from the leaves that it eats.

Giraffe normally live to around 38 years and do not normally face predators due to their size, eyesight and powerful kicks. however, prides of lions are capable of making a kill on the smaller animals suck as calves and also younger adults. The mothers defense is to stand over her calf and kick when the calf is under attack. Despite this brave stand many calves are killed when only a few months old.

Giraffes spend most of their lives standing which includes sleeping and even giving birth. The calf enters the world with a 1.5 m drop and is able to run within 30 minutes. As far as sleeping goes, they typically do power naps of around 5 minutes at a time and sleep up to about 4.5 hours in a day.

Photo by Christels from Pixabay.

There is a most interesting book called Zarafa by Michael Allin which tracks a giraffes journey from Africa all the way to Paris. It was a gift from Muhammad Ali, the Ottoman Viceroy of Egypt to King Charles X and the animal became a sensation as it progressed. She survived in France for about eighteen years but it was quite a story to get her there.