Dog
The domestic dog has evolved what researchers term hypersociability, a genetic predisposition towards seeking human contact that distinguishes it from its wolf ancestors. Studies at Princeton University identified specific genes associated with this trait, mutations that essentially encoded dogs for friendliness over millennia of selective breeding. The average dog approaches humans with what can only be described as excessive optimism, tail wagging at frequencies that correlate with emotional arousal.
This approachability serves practical functions. Dogs are employed as therapy animals, assistance companions, and social facilitators precisely because they do not require extensive negotiation before permitting contact. A well-socialised dog will accept attention from strangers with enthusiasm bordering on the undignified.
Swan
The mute swan has cultivated an approach to human interaction best described as strategic hostility. Whilst capable of tolerating human presence when food is offered, swans maintain a baseline attitude of suspicion that can escalate to open aggression with minimal provocation. During breeding season, which conveniently spans most of the pleasant weather months, swans defend territories extending up to four hectares with a commitment that military strategists might admire.
Their approach is characterised by warning displays, wing-arching postures designed to maximise apparent size, followed by direct charges at perceived threats. The fact that swans have successfully intimidated grown adults into retreating from public footpaths speaks to the effectiveness of this strategy.
VERDICT
Dogs were literally engineered for approachability. Swans appear to have been designed by nature to discourage casual interaction with maximum prejudice.