Contact Form 7 Data Placeholder not showing

Hello. On this page http://bib.vergedesign.co.uk

the contact form at the bottom has a data field, for which i have added a placeholder. However instead of the placeholder showing the date fields (to select the month, date, year etc) are showing. I would prefer those only showed once the field was clicked on.

This is basic CF7 stuff... why isnt the placeholder showing?

Please find my code below.

<div class="row text-center">

<div class="col-xs-6">
<label>[text* first-name placeholder "First Name*"] </label></div>

<div class="col-xs-6">
<label>[text* last-name placeholder "Last Name*"] </label></div>

<div class="col-xs-6">
<label>[text* postcode placeholder "Postcode*"] </label></div>

<div class="col-xs-6">
<label>[date* dob min:1960-01-01 placeholder "Date of Birth*"] </label></div>

<div class="col-sm-12">
<label>[email* your-email placeholder "Your email *"] </label></div>

<div class="col-sm-12">
[submit "Send"]
</div>
</div>
</div>