head shot of two hippos in water

abstract africa african aggressive animal animals aquatic big body botswana brown captivity creature danger dangerous day ears eating eye fat float glide green head headshot hippo hippopotamus hippos horizontal huge isolated large mammal mother mouth natural nature nobody nose nostril old outdoors pool postcard preservation preserve rights ripple rise river safari savage serengetti shot size skin slow small strong swim swimming threat threaten threatening tough two underwater water wet wild wilderness wildlife zoo zoological