The Leafy Sea Dragon – Did You Know?

In my Did You Know series, learn some fun facts about an animal in 5 minutes. I’ll tell you stuff you didn’t already know (hopefully). Let me know if I surprised you!

Today I’ll tantalise your curiosity taste buds with a master of masquerade: the leafy sea dragon.

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The leafy seadragon or Glauert’s seadragon, Phycodurus eques. Photo credit: James Rosindell

Did You Know?

  • It is a species of fish named after the dragons described in Chinese mythology and folklore (and more recently in George R. R Martin’s Game of Thrones)
  • It is the only member of the Phycodurus genus in the Syngnathidae family of fishes.
  • Its resemblance to a piece of drifting seaweed may help to protect it from predators. Its seaweed-like appearance not only allows it to match the background of seaweed and kelp it lives amongst (making it very hard for predators to spot), but it may also serve as a type of camouflage called ‘masquerade’. This is when an animal tricks its predator into thinking it’s an inedible object that isn’t dinner, similarly to that seen in leaf and stick insects. If you’re interested, you can read more about masquerade here and here.
  • Another aspect of this ‘floating seaweed’ trick seems to be the sea dragon’s sedate movement through the water. It moves at a slow rate of about 150m per hour propelled by fins along the side of its head but often stays in the same place for long periods of time.

 

 

  • Unusually in the animal kingdom, the male is the sole responsible parent. The female deposits 150-250 bright pink eggs onto the male’s tail, and then leaves him to it. He carries them in a honeycomb-like structure called the brood patch for 8 weeks where they are supplied with oxygen until the young emerge (like its relatives: seahorses, pipefish and other sea dragons). Only about 5% of the eggs survive and the young are completely independent at birth.
  • It feeds exclusively on small crustaceans like mysid shrimp.
  • Their natural habitat is calm, cold water (10-12 degrees Celsius) in the southern coasts of Australia, where they are known locally as ‘leafies’.
  • It is classified as Near Threatened by the IUCN Red List 2006, and may even be reclassified as Endangered, mainly due to habitat loss and pollution through human activity.
  • It has been protected by the Australian government since 1982 and is the marine emblem for the state of South Australia.

Thanks for reading and look out for other posts in my Did You Know? series!

Choosing the best of the nests makes sage grouse good mothers

Recent research published in  The Condor: Ornithological Applications has shown that greater sage grouse mothers (Centrocercus urophasianus) can choose nesting habitats that better ensure the survival of their chicks after they fledge.

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Female greater sage-grouse (Centrocercus urophasianus) [front of image] can select nesting habitats that ensure their offspring survive. Photo credit: Jeannie Stafford/USFWS.
Evolution not only drives animals to act to benefit their own survival (direct fitness) but also that of their own offspring (indirect fitness). Maximising such lifetime reproductive success is probably what drives us to protect our own children.

But can animals actually make active decisions that benefit their reproductive success? This is the question that Dr Daniel Gibson and his colleagues set out to answer in their study of the greater sage grouse.

These birds are the largest grouse in North America, inhabiting open grassland habitats that make them particularly vulnerable to predators. The species is classified as Near Threatened by the IUCN Red List. They have a complex mating system, whereby males gather in groups (leks) to perform lively, colourful mating displays to attract females [see picture]. This means that females get to be extremely picky about who they mate with.

Dr Gibson and his team found that females are not only choosy about their sexual partners but also are picky about where they nest. They tend to choose nesting habitats with characteristics that ensure reproductive success: specifically, greater shrub cover and forb (flowering plant) diversity. By observing over 200 mothers over a period of 8 years, they found that these habitat features predicted the survival of chicks after fledging.

This means that even our feathery friends can make active choices that determine the survival of their offspring, which is pretty impressive. What isn’t so clear is whether the mothers themselves were more likely to survive – were they also acting to protect themselves as they sat helpless on their nests? Or is their behaviour purely selfless?

Whatever the answer, it is likely that many other animals are able to protect their young by making these real-time decisions – what can be termed ‘behavioural plasticity’ – something that evolution is likely to promote in order to maximise indirect fitness and pass on genes to future generations.

Knowing this will also help conservation efforts because land managers now have clues about where these birds are most likely to nest, and hence which habitats they should protect the most.

 

 

Scientific American video about my research on lizard camouflage

Scientific American have produced a great video about my PhD research on lizard camouflage in Greece. I found that lizards are able to pick certain rock backgrounds to sit on that make them most camouflaged to a predatory bird’s eye. Intriguingly, this means that somehow they know the colour of their own backs and how well it will match a given rock – a puzzle I haven’t quite worked out yet. You can watch the video here.

 

40 Words For Emotions You’ve Felt, But Couldn’t Explain | Thought Catalog

Have you ever felt an emotion but had no word to describe it? Then consult this post by Brianna West on thoughtcatalog.com. It helpfully lists 40 words that will perfectly cure that lost-for-words, tip-of-the-tongue feeling.

So next time you have a hanker sore, you can relieve it with a bit of ambedo. I dare you to start using them in your everyday conversations and writings. It’s time for some liberosis, people. 

Underwater shipwrecks hold secrets to life as well as pots of gold

The tragic event of losing a ship at sea is one that has occurred far too often in history. The sad remnants of sea-ravaged ships lying forgotten underwater for hundreds of years not only tell us secrets about the disastrous events themselves but also hold valuable physical clues to past times we know little about, including actual treasure troves of gold and jewels. Not surprisingly then, shipwrecks have long intrigued painters, writers, scientists, filmmakers, historians and even professional treasure hunters alike.

We only need to think of the (arguably) hit film The Titanic, in which Kate Winslet and Leonardo DiCaprio are immortalised as tragic lovers on a ship bound for the bottom of the Atlantic. The poem The Wreck of the Hesperus by Henry W. Longfellow even inspired a song by The Beatles’ George Harrison, and is a term my mum uses to describe me when I’m looking particularly unkempt. So it seems that shipwrecks have had such an impact on us that they have even infiltrated the English language.

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The Wreck by Knud-Andreasson Baade c.1835. Wikipedia Commons.

Shipwrecks also have remarkable stories to tell us about the past. With rapid advances in technology, we now have sophisticated remote-sensing and remotely operated diving equipment, allowing diving archeologists to find and reach much deeper underwater sites, meaning that no site is beyond the reach of our research into the past. We only have to think of the 2003 discovery of the shipwreck of The Santa Maria off the coast of Haiti – one of the ships now thought to have carried Christopher Columbus over the Atlantic to America – and the excavation of the 2,000 year-old Antikythera shipwreck to uncover ancient treasures including the world’s first known computer.

Now, scientists have uncovered other secrets related to the rich and deep ecosystems that shipwrecks support in the Gulf of Mexico. Here, over 2,000 shipwrecks languish on the bottom of the sea spanning over 500 years of maritime history from the time of the 16th century Spanish explorers to the American Civil War and through the World War II era. A team of scientists have dived down to discover exactly what kind of life these ships support and how it has been affected by a huge and devastating oil spill in this area (the Deepwater Horizon oil spill in 2010).

In the first ever study of its kind plunging into deep-sea shipwreck ecosystems, the team discovered that the presence of shipwrecks on the seafloor alters what kind of microorganisms are found there. They also revealed that the chemicals used to clean up the oil spill has changed this microbial community, even after four years, thus having knock-on effects on other animals that depend on them like crabs, fish and coral.

The team also found that the oil spill could degrade not only the surrounding ecosystems but also the ships themselves, as the oil seems to increase metal corrosion on the ships’  surfaces. The researchers plan to use innovative 3D-laser and sonar technology to produce high-resolution images of the vessels to document how the oil spill affects their future state of preservation.

What I found most exciting about this study is that it shows how investigating deep-sea shipwrecks can help us monitor the rich ecosystems they support, as well as helping to preserve the precious historic value of the ships themselves. It could also help scientists studying other aspects of the deep sea – a huge part of our planet that still remains mostly a mystery to us.

One thing I am sure about is that the enigma that lies beneath the surface of our oceans  – the secrets of its dark history and ecological treasures – will continue to intrigue and inspire us for a long time to come.

A video about the research can be found here and was presented at the 2016 Ocean Sciences Meeting in New Orleans, U.S.A. yesterday.

Co-authors of the study:

Jennifer Salerno: George Mason University, Fairfax, VA, USA;

Brenda Little, Jason Lee, Ricky Ray: Naval Research Laboratory, Stennis Space Center, MS, USA;

Leila Hamdan: George Mason University, Fairfax, VA, USA.

The Platypus – Did You Know?

In my new Did You Know blog series, learn 10 facts about one animal in 5 minutes. In the series, I’ll tell you stuff you didn’t already know (hopefully). Let me know how many surprised you!

Today I’m going to blow your mind about an ancient mammal: the duck-billed platypus.

Did You Know that platypuses…

1. …Are one of only five mammal species that lay eggs instead of giving birth to live young (Monotremes). The other four are species of echidna. The eggs develop internally for 28 days and are incubated externally for 10 days. The platypus genome has both reptilian and mammalian genes associated with egg fertilisation.

2. …Are one of very few venomous mammals. The male has a spur on the hind leg that can cause severe pain in humans.

3. …Is a recognisable and iconic symbol of Australia. It is endemic to eastern Australia, including Tasmania, and appears on the reverse side of the Australian 20-cent coin.

4. …Completely stunned European naturalists when it was first discovered in 1798. The specimen of a bizarre duck-billed, beaver-tailed, egg-laying mammal was first thought a hoax.

5. …Is the only type of mammal (except some dolphins) to use electroreception. Monotremes (platypuses and the four echidna species) can locate their crustacean prey by sensing the electric fields caused by their muscle movements. A sheet of electroreceptors is found on the bill. By shaking its head from side-to-side while swimming it can detect differences in signal strength to sense the direction of the electrical source.

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The platypus (Ornithorhynchus anatinus) is one of the world’s most primitive mammals. John Gould print image: Wikipedia Commons.

6. …Closes its eyes, ears and nose when it hunts underwater. Solely relying on electroreception and sense of touch (mechanoreceptors) on the bill, prey are found by detecting both the electrical fields and mechanical pressure pulses they emit. The different arrival times of these two signals to the bill signify the distance to the prey.

7. …Have unusual eyes among mammals. Their poor vision is more similar to Pacific hagfish than to other tetrapods (vertebrates higher than fishes) and the eyes contain double cones involved in luminance (brightness) perception, which most mammals do not have. Although vision may have been important for hunting in distant ancestors, this may have been sacrificed for the electrosensory system that is better suited to an aquatic and nocturnal lifestyle.

8. …Have a unique swimming motion among mammals. Webbed feet propel them through the water, although only the front feet are used for power in an alternate rowing motion; the hind feet and tail are used for steering.

9. …Feed their young with milk released through pores in the skin. Although platypuses have mammary glands – one of the defining features of a mammal – they lack teats. Instead the blind, helpless and naked young drink milk that pools in grooves on the mother’s abdomen.

10. …Are descended from the extinct monotreme Steropodon.  The fossilised specimen is thought to be about 110 million years old, making it the oldest mammal fossil to be found in Australia. Another fossil relative, Monotrematum sudamericanum, can be placed in the supercontinent Gondwana (when Antarctica joined Australia and South America) up to about 167 million years ago.

Feel free to make suggestions about other animals you want to see featured in the series!