Heedless Ways

Chimpanzees in Uganda’s Kigali National Park have been getting up to some unusual business at night. These daytime foragers with poor night vision have been leaving the safety of the forest, crossing a bridge over a large ditch meant to keep elephants out of neighboring crop areas, and raiding corn fields.

And they aren’t the only ones. Chimps in other areas are raiding farmers’ fields, as well.

Why is this noteworthy?

Chimpanzee hand Artist: Lisa Roet

Chimpanzee hand
Artist: Lisa Roet

Well, according to a study out in PLOS ONE, this is the first recorded evidence that day-dwelling chimpanzees have significantly altered their behavior to include night-time feeding parties. Unlike some forest animals, chimpanzees’ eyes are not particularly suited for low-light vision, yet they are entering fields after sunset, and often during the darkness of a new moon.

Another development is that the raiders carry their food away with them, rather than eating it on the spot as usual. In doing so, they’ve overcome their own evolutionary wiring to eat during the day and avoid traditional nocturnal predators, like the jaguar, which has all but died out in these regions.

With habitat loss turning once-dense forests into mosaics of cultivated acreage and trees, and a reduction in the fruits usually eaten by the endangered chimps, the maize growing in nearby fields must seem like a decent alternative, if snares and farmer’s weapons can be avoided.

Primate finger Artist: Lisa Roet

Primate finger
Artist: Lisa Roet

One can’t help but admire the chimpanzees’ audacity and creativity in the face of necessity, and their unwillingness to simply starve.

It put me in mind of one the best-known poems of Dylan Thomas, who would have celebrated his 100th birthday today:

Good men, the last wave by, crying how bright
Their frail deeds might have danced in a green bay,
Rage, rage against the dying of the light.

Now the question is, how well will government, conservation groups and farmers adapt to innovative chimpanzee behavior?

A few other examples of new adaptations, some less successful than others:

North American populations of the monarch butterfly, decimated over the years mainly due to deforestation in the wintering habitats of Central Mexico and the loss of milkweed plants, the monarch’s main choice of food, to industrial farming and pesticides. In an encouraging and unexpected turn of events, deforestation activity seems to have slowed, allowing the monarch to recover, at least for the time being. Deforestation, and milkweed prevalence, are two factors well within human control, so the monarch is adapting to our habits–and once in a while, we adapt to the monarch’s.

Walrus tusks, fossilized Source: Alaska Fur Exchange

Walrus tusks, fossilized
Source: Alaska Fur Exchange

A very large cluster of walruses was in the news for a few days in early October. As in previous years, tens of thousands of the sea mammals gathered on dry land when the sea ice that usually forms the platform from whence walruses hunt melted early in the feeding season. A gathering of walruses is known as an ‘ugly’, not a very kind term for such an interesting creature, but perhaps descriptive of what happens when too many of them all find themselves on the same beach, commiserating over meagre ice and elusive food. The 2014 ugly has since broken up and moved on to further shores, but given the current negative trends in Arctic sea ice, whether the walrus succeeds in surviving remains to be seen.

Arctic Dreams Artist: David Dancy-Wood via Wildlife Sketches

Arctic Dreams
Artist: David Dancy-Wood via Wildlife Sketches

The disappearance of ice platforms in the Arctic region has a number of species scrambling to maintain a foothold, among them the polar bear, whose populations have been in drastic decline as their hunting habitat melts beneath them. Stuck on land (well, the ones who make it to land), they have replaced their diet of seal and fish with Arctic birds and human garbage (and even, occasionally, other polar bears).

And again, what of our abilities to adapt our own behaviors, not just to make adjustments for the protection of these various iconic creatures, but when it comes to making the changes that won’t put us in situations similarly dire?

In the sun born over and over,
I ran my heedless ways,
My wishes raced through the house high hay
And nothing I cared, at my sky blue trades, that time allows
In all his tuneful turning so few and such morning songs
Before the children green and golden
Follow him out of grace.

(Dylan Thomas, Fern Hill)

Newness, Past and Present

I noticed two items this week regarding species previously unknown to us. They’ve both been labelled ‘new’, although they are anything but new.

The first is a long-extinct sauropod, the largest yet discovered, which has been given the truly magnificent name Dreadnoughtus schrani, ‘that which fears nothing’. As a quadruped the size of a Boeing 737, I imagine the only thing a Dreadnoughtus might have had to fear was a lack of plant material to forage.

Or, in the case of the Dreadnoughtus individual found in Argentina, quicksand. The creature was preserved when it and other dinosaurs perished in the Patagonian hills an estimated 77 million years ago.

Dreadnoughtus scharni Source: E. Eng, National Geographic, M.C. Lamanna, Carnegie Museum of Natural History

Dreadnoughtus scharni
Source: E. Eng, National Geographic, M.C. Lamanna, Carnegie Museum of Natural History

The other find involves a sea animal that is, presumably, still extant in the oceans off Tasmania. No one is really sure.

Dendrogramma enigmatica and Dendrogramma discoides Source: Kristensen, Olesen/PLOS ONE

Dendrogramma enigmatica and Dendrogramma discoides
Source: Kristensen, Olesen/PLOS ONE

Dendrogramma eingmatica (another wonderful name) is a tiny mushroom shaped being with a long stalk and a mouth. After much examination, what is really new about Dendrogramma is that the two species don’t fit into any existing phylogenetic classification.

They seem to comprise their own little branch on the Tree of Life.

Dendrogramma Source: Kristensen, Olesen/PLOS ONE

Dendrogramma
Source: Kristensen, Olesen/PLOS ONE

I was never comfortable with the fact that when we perceive a natural entity that we haven’t seen before, whether it’s a species, a geographical feature or a planet, we say we’ve ‘discovered something new’.

It implies that only what we humans have seen and identified actually counts as existing.

The Dendrogramma specimens under discussion were harvested in 1986, and preserved in such a way that DNA analysis can’t be applied. Until new specimens are found, and maybe even after, their provenance will remain a mystery.

New to us, not really new at all.

 

Sessile Mobility

Sucker-footed bat Source: Guardian Live

Sucker-footed bat
Source: Guardian Live

A study on sucker-footed bats (Myzopoda aurita), published in PLOS One, discusses bat fossils found in Egypt’s Western Desert. This might be less worthy of examination if the fossils weren’t almost identical with existing bats now found only on Madagascar. These bats have sessile, or immovable, pads for feet.

Based on their research, study authors were able to reach a couple of interesting conclusions based on these tiny, ancient bat jaws. For one thing, the fossils provide evidence of a bat lineage that is 37 million years older than previously assumed.

Animated illustration of the break-up of Gondwana into present-day continents. Based on the bat fossils found, it's assumed that bats which originated in Africa, migrated into Australia, and were able to cross Antarctica into what is now South America. Source: Churchilll Science

Animated illustration of the break-up of Gondwana into present-day continents. Based on the bat fossils found, it’s assumed that bats which originated in Africa, migrated into Australia, and were able to cross Antarctica into what is now South America.
Source: Churchilll Science

This finding, in turn, provides evidence of when and how continental drift took place – the bats were apparently able to cross between continents while the land masses were either still attached, or while there were still dry land bridges between them. Continental drift contributed to the diversification of the bat family by separating and isolating their various groups. The sucker-footed bat was likely once more widespread.

Photo: Merlin D. Tuttle / Bat Conservation International

Photo: Merlin D. Tuttle / Bat Conservation International

In any case, the modern bat with the feet of a tree frog and that lives on Madagascar is the real reason I wanted to post this today. Because they are the only kind of bat that doesn’t hang upside, they live in palm fronds, they have ears that look like their palm frond homes, and they hang on to the slippery surface of leaves using feet that look like something from a child’s drawing.

Group of bats inside a palm leaf. Source: Arkive

Group of bats inside a palm leaf.
Source: Arkive

Paper Parks

Paper lion - an historic French West Africa banknote (1926)

Paper lion – an historic French West Africa banknote (1926)

A team of researchers spent six years tracking populations of West African lions (Panthera leo), a breed genetically distinct from other lions on the continent. Twenty-one parks exist for their protection, but according to a study out in PLOS ONE, lions were actually found in only four of these parks.

Lions are protected throughout Africa, with millions of dollars spent in conservation efforts – just not in West Africa. The lion population – estimated to be at under 400 individuals – has been divided, encroached upon, hunted. Habitat destruction due to farming, and the large bushmeat market that competes with the lions for prey, have done most of the harm.

The research team and the IUCN (International Union for Conservation of Nature) are calling for immediate investment in protection of this species, but considering that West Africa is among the poorest regions on the planet, this will be an uphill march.

Dr. Philipp Henschel, survey coordinator for Panthera, the non-profit wild cat conservation organization that sponsored the survey, led a team that examined lions across 17 countries. I heard Dr. Henschel interviewed on the BBC.

In addition to the plight of these animals, one image of his particularly struck me: He and his colleagues devoted years to the survey before ever laying on a living West African lion, symbol and emblem of West Africa. They went from park to designated park, only to find the lions had disappeared.

They had thought they would be counting lions, but they spent most of the survey counting paper parks – parks in name only, the subjects of protection already long gone.

Social Climbers

Emperor Penguin colony. The adults are the size of a large dog.
Credit: Zibordi / Van Woert, NOAA NESDIS, ORA

The Emperor Penguin (Aptenodytes forsteri) is big, as birds go, and as graceful underwater as it is ungainly on land. Its native habitat is Antarctica, and until recently, the bird has been considered ‘sea-ice obligate’, meaning it breeds and forages from sea-ice platforms.

The species hasn’t been considered under threat for time being, but given the changes that are occurring in its one and only habitat and the increasing instability of sea ice platforms, most long-term predictions are less than optimistic.

The Emperor likes to nest at the same sites year after year, and those sites do not always oblige any more by appearing in a timely manner.

However, the Emperor Penguin’s strong preference for keeping a regular breeding address might be matched by an unexpected adaptability in another area: its previously unknown climbing skills and its willingness to try something new.

Emperor Penguins on the edge of the Larsen Ice Shelf near the Jason Peninsula late in the breeding season. Note the ice cliff which is probably an insurmountable barrier to the adult emperor penguins. No evident route to the colony was determined from the images. Caption/Photo: Fretwell et al. / Ian Potten

Emperor Penguins on the edge of the Larsen Ice Shelf near the Jason Peninsula late in the breeding season. Note the ice cliff which is probably an insurmountable barrier to the adult emperor penguins. No evident route to the colony was determined from the images.
Caption/Photo: Fretwell et al. / Ian Potten

A new study has shown that there are colonies of Emperor Penguins that have reacted to the unreliability of sea ice in their usual spots by relocating to a higher elevation on a permanent ice shelf. It seems that thousands of penguins, rather than look for new sea ice platforms, instead trekked up sloping ice creeks and gullies to safer locations.

This doesn’t mean the species isn’t threatened by climate change in the long run.

Rather, it’s a surprising and positive illustration of adaptation to rapidly changing conditions.

Source:

Fretwell PT, Trathan PN, Wienecke B, Kooyman GL (2014) Emperor Penguins Breeding on Iceshelves. PLoS ONE 9(1): e85285. doi:10.1371/journal.pone.0085285

Long Forest View

A study out this week has reconstructed an image of what one area of pre-European forest looked like in the North American area of what is now Pennsylvania. From this artist’s interpretation, at least from a distance, it looks like, well, like a forest.

But prior to European settlers’ intensified land clearing, the mill-building, the agriculture and industry, the trees were different trees, by and large, and entire waterways and ecosystems were very different.

Artist's reconstruction of the pre-settlement landscape as here interpreted using plant macro fossils Credit/Artwork: S. Elliot et al/Rebecca Wilf via PLOS ONE

Artist’s reconstruction of the pre-settlement landscape as here interpreted using plant macro fossils
Credit/Artwork: S. Elliot et al/Rebecca Wilf via PLOS ONE

There are several mill dam reconstruction projects underway, and it is hoped that gaining a more profound understanding of   the pre-settlement forest and waterways will support those efforts. Many of the trees that were present still exist, but in different ratios and different places. Some of the species, like the American chestnut, have since died out due to disease.

 

In a poignant irony of paleohistory, one of the very mill dams that led to the changes in the forest system was the reason researchers were able to study its characteristics.

The fossilized leaves that would offer an in-depth picture of bygone forest trees are typically not easy to find. But researchers examining the effects of mill dams on water levels and waterways made a find of leaf fossils from hardwood trees that was preserved in a layer of pre-dam river mud.

It might otherwise have been long since washed away – but it was buried under a layer of sediment from the construction of a mill dam 300 years ago.