They can. There wre vwrious symptomes : loss of apettite, drinking more water, vomiting, increased urination.
I suggest you to take a look at this webpage: http://pets.webmd.com/dogs/guide/dog-diabetes-symptoms-treatment
I have had 3 and they were not diabetic but you should not give dogs sweets because sweets and canned dog food can gunk up their teeth and make it hard to brush them ! Dogs are not humans so do not expect them to get everything that humans get ! Just like humans wear glasses do to bad vision but do you take a dog to get glasses ? No , so do not believe others about animals becoming diabetic anymore then having two dogs get married like humans do ! Thanks
I have had 5 dogs ! They are not suppose to have sweets or be around poinsettias for these are hazardous to a dogs health ! Keep your dog away from all plants and sweets ! Thanks