Wildlife
Plus: hybrid birds, a new study on tiger sharks, the importance of parks and octopuses that throw
An outbreak of distemper among Toronto’s raccoons has overwhelmed Toronto Animal Services. With so many dead animals, it is taking up to two weeks to collect the bodies versus the usual 48 hours and Solid Waste Management Services and Transportation Services has been called in to help. Distemper, which is a viral infection caused by the canine distemper virus, typically ramps up every two or three years with outbreaks occurring between May and November then subsiding as the weather cools. On the positive side, the outbreak poses almost no risk to humans or other animals.
A new study has found that tiger sharks that interact with tourists have higher hormone levels and are generally larger than those that don’t. Co-authored by a Carleton University researcher, the study looked at tiger sharks in the area of Tiger Beach, Bahamas. The beach is known for its tiger sharks and offers tourists the chance to feed and interact with them. Local operators attract the sharks by throwing fish into the water. To identify which sharks frequented Tiger Beach, spatial use data from acoustic transmitters was collected over a 90-day period. Researchers found that the area is dominated by large females, some of them pregnant. Hormone and fatty acid levels were higher in these sharks compared to those (usually juvenile) found in areas without tourist interaction. “We don’t know exactly why this was. Levels of these hormones might have been higher as part of their more aggressive social dominance behavior while they were swimming with many other sharks,” says Renata Guimarães Moreira, one of the study’s authors. While they can’t say if tourism is harming these sharks, the findings shed light on the importance of considering cycle stages, hormone levels, and nutritional states when assessing the impact of tourism on shark diet.
Bird of a feather, flock — ahem, mate — together? New research published in Global Change Biology has found that hybrids of two common North American songbirds — the black-capped and mountain chickadee — are more common in places where humans have altered the landscape. The study is the first to examine the correlation separate from climate change. (Climate change can lead to overlaps in range, bringing together species that did not used to have contact.)
“What are the consequences of the ways we modify the landscape? We think about it mostly in terms of habitat loss, not necessarily in terms of species interaction modifications,” said Scott Taylor, co-author on the study. The hybridization is unlikely to lead to the creation of a new chickadee species as the female hybrids from black-capped and mountain chickadee parents are likely to be sterile. Male hybrids can reproduce and seem to do so predominantly with black-capped chickadees. “It’s hard to say whether this hybridization is good or bad, but it’s happening, and we will only understand the impacts through continued study,” said Taylor in a news release about the findings.
Some octopuses can predict World Cup results. Some are cunning escape artists. In others, like the one featured in the multi-award-winning My Octopus Teacher, we can catch a glimpse of our own humanity. And others….chuck stuff at each other.
A team of scientists, including Stefan Linquist at the University of Guelph, documented gloomy octopuses (“gloomy” being the species name; not their mood) in Jervis Bay, Australia, throwing shells, silt and algae at themselves and at each other. These tentacled tossers release their marine projectiles from their arms, propelling them through the water using a forceful jet from their siphon.
“Some throws appear to be targeted on other individuals,” write the authors in their paper published in PLoS ONE, noting that some throws were more vigorous than others, often accompanied by a darkening of body colour. Most throws missed other octopuses, but “octopuses in the line of fire ducked, raised arms in the direction of the thrower, or paused, halted or redirected their movements.”
Throwing behaviours are rarely documented in nonhuman animals — perhaps another case of seeing a glimpse of our own humanity in our cephalopod chums.
A recent CBC story about White Tower Park in Gibsons, B.C., highlights the idea that parks are far more than a lovely place for a stroll — if designed right, their ponds and culverts can soak up water, protect nearby towns from flooding, and replace the need for pipes. White Tower Park is a poster child for how natural landscapes can replace traditional infrastructure. The park’s ponds, which soak up stormwater and collect runoff, act as a replacement for pipe systems that would otherwise have cost about $3.5 million plus and an average of $80,000 to repair each year. Gibsons funded the project by putting a price on nature infrastructure. It began investing in nature back in 2012 by changing the definition of infrastructure to include “nature assets.” This step allowed the town to advocate for finances to maintain areas like wetlands, parks and forests while also utilizing their benefits. Gibsons’ green incentives have inspired other areas across the country to redefine the definition of what infrastructure is, including Canada-wide Municipal Natural Asset Initiative. Changes like this will help encourage municipalities to work with the environment instead of building through it.
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