Eggs have to be fertilised by a male. The video shows male and female frogs mating
to produce frog spawn
Which is smaller, male or female? Rollover the frogs to see if you are right
When a male sperm joins with a female egg the egg is fertile and can grow
Sperm cell joins with egg cell
The male, on top, is much smaller. The female produces so much spawn she has to
be bigger
1 By Richard Bartz, Munich Makro Freak (Own work) [CC BY-SA 2.5 (http://creativecommons.org/licenses/b y-sa/2.5)],
via Wikimedia Commons
2 By Salimfadhley (Photo taken by Salimfadhley) [GFDL (http://www.gnu.org/copyleft/fdl.html)
or CC-BY-SA-3.0 (http://creativecommons.org/licenses/ by-sa/3.0/)], via Wikimedia
Commons
By Pristurus (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)],
via Wikimedia Commons