Node REPL + Underscore returns no method

Just getting started with Node.js and would like to try out Underscore to test out some ideas.

I've read post here, here and lastly here.

I get why using the _ does not work in a REPL. But neither does reassigning the underscore object.

For instance,

 > var _u = require('underscore');
   { _: 
    { [Function]
      VERSION: '1.0.2',
      forEach: [Function],
      map: [Function],
      reduce: [Function],
      reduceRight: [Function],
      detect: [Function],
      ...feeling good about myself...

 > _u.uniq([1,2,3,4,4,44]);

Returns:

TypeError: Object #<Object> has no method 'uniq'
at repl:1:4
at REPLServer.self.eval (repl.js:109:21)
at rli.on.self.bufferedCmd (repl.js:258:20)
at REPLServer.self.eval (repl.js:116:5)
at Interface.<anonymous> (repl.js:248:12)
at Interface.EventEmitter.emit (events.js:96:17)
at Interface._onLine (readline.js:200:10)
at Interface._line (readline.js:518:8)
at Interface._ttyWrite (readline.js:736:14)
at ReadStream.onkeypress (readline.js:97:10)

Any ideas on why this could not work besides rename the global underscore object? The version assigned to _u is 1.0.2.