I noticed that also. Right now Bitcoin's dominance is at about 43% which is way higher than the thirty something we had a few months ago. I think that generally is Bitcoin that leads a rally and "the first money" to come are thrown at it and then people and institutions start selling it and buy alts growing them in price also. For the moment though its dominance is huge and I think it will remain on these levels for some time. I am not a trader thus I don't care that much about satoshis on my altcoins.