There is no doubt that bats and ostriches have captured the fascination of many people over the years with each of their unique evolutionary paths. How can a mammal be capable of flying, while a bird can’t? Bats, with their elongated fingers, adapted to form wings soar across the night sky, while ostriches, the largest living bird, have given up the ability to fly and adapted to a terrestrial lifestyle, becoming one the fastest runners on land.
These adaptations continue to bewilder us, but each is vital for them to thrive in their respective niches.
Bats – The Masters of Flight
The evolutionary history of bats can be traced back over 50 million years and most likely to a small insectivorous mammal that inhabited forested environments. Although palaeontologists still haven’t confirmed which mammal bats may have evolved from, they likely developed the ability to fly to escape predation and/or to pursue an abundant supply of flying insects. Unlike birds and pterosaurs (an extinct clade of flying reptiles), in which the wing is supported by the bones of the arm and one finger, a bat’s wing membrane (patagium) is supported by the arm and by four elongated fingers. Hence the Greek name Chiroptera meaning ‘hand-wing’ which bats are commonly referred to.
A Dwarf Epauletted Fruit Bat (Micropteropus pussilus) shows off its elongated fingers and flexible wing membrane that resists tension while the stiff wings of birds in comparison deliver bending and torsional stress to the shoulders.
This unique adaptation allows bats to navigate through complex environments, even in complete darkness. How do they manoeuvre through the night skies? Just like other nocturnal mammals, bats’ eyes are made up of more photoreceptor cells called rods, which maximise their ability to see in the dark (this is as opposed to cones that maximise colour vision). However, nocturnal vision alone wasn’t enough. Bats are synonymous with echolocation whereby they send out ultrasonic sound waves to locate and prey upon insects with incredible precision. This prime example of convergent evolution opened up new ecological niches for bats to explore, leading to their eventual success as one of the most diverse and abundant groups of mammals on earth.
Wahlberg’s Epauletted Fruit Bat (epomophorus Wahlbergi). Bats’ diverse diets, including insects, fruits, nectar, and small vertebrates, showcase their exceptional adaptations to various ecological niches.
Ostriches – The Flightless Bird
Ostriches, on the other hand, belong to the avian family and their ancestors can be traced back to around 40 million years ago. Initially, these birds were capable of flight, but their evolutionary journey took a different turn. In contrast to bats which took to the night skies to avoid competition over food on the ground, ostriches, emus, and other related flightless birds mainly obtained their food from the ground. As a result, there was no need for flight to search for their food, and over time, they became bulky and their wings became too weak due to a lack of use across generations. While ostriches still possess feathers, the individual barbules are not interlocked in the same way as a flying bird’s feathers, resulting in the feathers offering no wind resistance for them to get off the ground.
This ostrich shows off its powerful legs as it chases off a herd of buffalo approaching her clutch of eggs.
Along their evolutionary path, ostriches have instead developed long, powerful legs granting them the distinction of being not only the fastest running bird at 70km/h (45mph) but also the largest living bird (males at a maximum height of 2.75m/9ft and 130kg/290lbs). Ostriches are also known for their two massive toes, in comparison to most birds which have four toes. The inner toe also has one large nail that appropriately resembles a hoof and aids in traction allowing them to reach their impressive speeds. These combined evolutionary adaptations along with their herbivorous lifestyle have assisted them to have a considerable advantage in their native arid and semi-arid habitats.
While many evolutionary paths may pique our interest, the mammal that flies and the bird that runs certainly stand out and present fascinating examples of divergent evolution, where unique adaptations have shaped their distinctive identities. Yet another marvel of the natural world to appreciate! Let me know in the comments if any other evolutionary paths have you bewildered.
Kelsey, thank you for the review of the bats and ostriches. They are unique animals in natures kingdom and Londolozi is lucky to have them.
Thank you William, we are very privileged with the diversity we have here at Londolozi!
Hi, any news on Londolozi ostrich families? If you want to add a “classic ” example to convergent evolution you may add a moth or butterfly. The opposite, divergent evolution most classic is the example of Darwins finches and their beaks shape. Other examples are the pangolins, occurring in Africa and Asia, the Southern American armadillo and the Australian echidna. Or marine creatures such as whales, seals, turtles, fishes… or, one of the most intriguing regarding eyes, such as humans and octopuses.
The ostrich family continues to grow, with a new male also appearing regularly in the northern section of the reserve. Thanks for the ideas Francesca, these are all fascinating examples 🙂
Kelsey just look at the Whalburgs bat and the fruit they eat are nearly the same colour in the foto you shared. The ostrich is quite a large bird and gets very aggressive if you come near its nest. The males are very protective towards his female and chick’s.
Great observation Valmai 🙂
This is great Kelsey – a mammal that flies and a bird that runs – spectacular!!
Pleasure Paul, I’m glad you enjoyed the blog!
Bats and ostriches are really extraordinarily interesting animals. The echo-location abilities of bats are amazing.
They are incredibly fascinating and impressive in many ways. I hope you are enjoying your visit 🙂
Unique comparison never thought about!
Thanks Anita, I’m glad you enjoyed the comparison.
Bats are certainly under appreciated. I simply adore them.
I agree and I’m happy to hear that you adore them Linda!