Inspiration: A friend posted to Facebook a ‘graph’ showing a figure (below) which, from different angles, can look like a rabbit or a duck, and captioned with a question about whether it was a rabbit, a duck or a dabbit. As it was more or less the Easter period, I imagined this in response.

No, what you’re looking at is a ruck, the carrying of which is the original purpose of what’s still known in some places as a rucksack.

According to the Cowford English Dictionary:
rucksack (noun) A special kind of backpack used in hunts to carry a specific kind of game, the ruck. Its use was common up until the 18th century, when the ruck went virtually extinct. Nowadays, the term’s meaning has expanded to refer more generally to a backpack.

Cross-referencing in the Encyclopaedia Notquitebritannica:
Ruck
An old species of game animal, a cross between a rabbit and a duck, which was hunted for centuries, to near extinction. In fact, for all intents and purposes, the naturally occurring ruck has all but disappeared. However, there is one strange phenomenon regarding the species. Once a year, over a period of a few weeks, new rucks appear. These are the result of strange cross-breeding. Indeed, certain species of wild rabbits and ducks near Cadbury’s chocolate factories in Britain have been known to engage in cross-species mating practices, usually occurring in late winter.
Scientists have hypothesized that certain waste products from the factories end up in their food chain, leading to this behavior. Nowadays, because of DNA incompatibilities and probably as a result of the proximity to the factories, the resulting cross-species eggs are not usually viable as living animals, and any live hatchlings don’t survive for long. In fact, in many cases the eggs have turned out to be made almost entirely of chocolate. According to leading theories, the variety of DNA combinations explains why some eggs are rather darker than others, while any additional flavors present can be attributed to the diets of the animals responsible for their conception. It has been rumored that Cadbury’s chocolates are encouraging the trend by feeding the rabbits and ducks and increasing the emissions of the factories, the purpose being to generate extra profits over the Easter period, an accusation the company has always vehemently denied.

The Cadbury’s Easter Egg Scandal (British BS Corporation summary from April 19th, 2016)
This spring, new evidence has come to light to the effect that the areas surrounding Cadbury’s chocolate factories in Britain contain abnormally large amounts of hazelnuts, almonds and other plants not native to the area. This has reignited old allegations about Cadbury’s deliberately influencing the ecosystems around its factories. Militant environmentalist groups have launched massive social media campaigns to accuse the company for pollution and environmental manipulation. Swiss chocolate maker Milka took the side of the environmentalists in this debate, complaining about the ‘unethical treatment of animals’ this shows. Cadbury’s maintain their position of staunch denial of these charges, stating that ‘passing tourists in these areas have left these nuts to feed the animals’.
Cadbury’s have also replied with counter-accusations, saying that Milka is well known in the chocolate industry for two blatant animal rights violations the Swiss government has clearly decided not to look into: Namely, that Milka genetically engineers its cows to produce chocolate in their milk (they say this is proven by the fact that the manipulation gives the cows a bright purple color), and the fact that they hire marmots to wrap their chocolate in aluminum foil before shipping it off to retailers. Cadbury’s even claims that this practice is seriously unhygienic and should be discontinued immediately. Other chocolate makers around the world have taken sides in this debate, and as of April 2016 no real result has come of it (though legal action is expected to be initiated soon by Cadbury’s, and official investigations by both Swiss and British authorities are rumored to be in the works).
Interestingly enough, Swedish frozen foods company Findus has chosen to take its own side by accusing both companies and has stated that they too will ‘file criminal charges against both companies’ for these unethical practices. This is generally perceived as a hypocritical threat, considering Findus has been involved in its own scandal a few years ago, about adding traces of horse meat to their prepared meals without properly informing consumers.