Dammit, my sodding reply got lost.
Um;
1/ Virus is not alive (doesn't count)
2/ If an insect or other animal was able to wipe out humanity, then it would be top of the food chain and hence 'higher'.
3/ Being a 'higher' form of life entails the combination of intelligence, ability to control environment, etc; not just the singular ability of one.
4/Territory is highly relevant. It's a perfect example of human intelligence and ability to adapt to other territories. I don't think there is a single advanced species (i.e. not single celled, etc, but reasonably intelligent) that has the 'range' humanity has.
5/All animals have brains or some form of CNS control.
6/RE: dolphin, etc, communications. Note that human communication is denoted by the ability to express complex thoughts via combination of terms. The range of our vocal cords, etc, has nothing to do with the intelligence or content of human communicaiton. At most it would mean dolphins et al could possible 'talk' faster.
7/It's completely pointless to bring up 'children as lower forms of life' as an argument (it's a lazy attempt to use a strawman IMO). Firstly, you'd have to compare human vs animal children at the same developmental stage where AFAIK humans have a far greater capacity for learning and larger brain mass. Secondly, children are still human; it's pretty obvious you don't partition species into age groups for definition, so you can't do so in comparison (unless you want a deliberately biased comparison). Thirdly, human children are by nature 'lesser' than adults; they are still learning, developing and have worse judgement amongst other things.
8/humanity ****ing up the planet is just evidence of our success as a species; No other species on earth has reached this level of control; it's not of any value to make assumptions that if another species reached this 'level', they'd be any better at managing the planet (in fact, they don't have the cognitive ability to identify a problem or communicate it, so they could be worse).
9/ the intrinsic 'balance' animals have with nature is simple environmental pressures. It's not attributable to that species 'intelligence' in doing so, just the interplay of competing plant and animal life.
10/Intelligence can be measured demonstratively; IQ test is just an attempt to put a specific rating on human intelligence, but it's daft to suggest that's the exemplar for all forms of 'intelligence test'.
11/The very concept of intelligence is a human one. As is every single arguement and counter arguement that can be used for this debate; you can't argue in terms of human perspective so long as you are human.