Wildshaping Druids do not, typically, gain the senses of the forms they assume.
Welcome to the abject insanity that is polymorphing in 3.5. For your specific question, the Alternate Form ability that Wild Shape is based on says:
The creature retains the special qualities of its original form. It does not gain any special qualities of its new form.
Since, in almost all cases, special senses like scent and blindsense are special qualities, this means that you don't get senses from Wild Shape.
Polymorph, and its related effects, are generally considered poorly written and poorly balanced in D&D 3.5, and are some of the most common effects that are houseruled or banned. Most of the alternate polymorph rules that I know change Wild Shape such that Druids can get their new form's senses, but by RAW, they do not.
That said, I'm absolutely certain that there's a way to get any sense you could name onto a wild shaping Druid. 3.5 is a huge set of rules, and that sounds like the sort of thing that would make it into a supplement at some point. One way is with the Enhance Wild Shape spell, on page 82 of the Spell Compendium. It lets you add one of several bonuses to your next wild shape, one of which is all of the extraordinary abilities of that form.
You just need to see one beast of its kind, not every possible phenotypic category of a kind of beast. If you did, it would specify that with something like
... the shape of a beast of a [gender/age/size/colour/seasonal pelt] that you have seen before.
It only specifies that you have seen that kind of beast before, nothing more.
Best Answer
I think the rule as intended is that you are familiar with the creature. I don't see any rules in the PHB about gaining additional shapes, so it comes down to the DM. (opinion)I would probably be okay with drawings with a nature check of some kind? Again, lots of ways to handle it.
Beside the standard "up to the dm" answer, let me link you an Unearthed Arcana PDF. On the last few pages, it provides more of a framework for those who want more concrete rules (Keep in mind this is playtest material). They suggest:
I am currently play testing that (as the DM) and love it.
Comment asks me to elaborate on my (opinion) above and the fact that I am using the UA.
Before the UA came out, we ran a homebrew game. A druid player was a bit upset that most of our campaign was urban / ghost hunting. They also felt uncomfortable asking to take the story from the group so they could watch bugs. Of course, I encouraged them to take the reigns, but also offered them the ability to study writings/drawings of the creature. Based on the level of knowledge they had, I'd set a DC (usually 15 or so) for a nature check). The role determined if he gained that beast shape or not. I admit this is a bit more "wizard"-y than a druid, but you could possibly consider combining the systems... give advantage on the check if they have a decent understanding of the creature.
At any rate, I would go with the UA article at this point. If the player wants to be some sort of nature documenter or something, I may tweak the system to make sure they have fun.